Fiona Frost/Synopsis

History
Nightfall was trained under Twilight to become a spy. Nightfall respected him so much that when he told her that a spy must never show their true feelings, Fiona pledged to "remain stone-faced for the rest of her life" and became a spy that did not let her emotions get in the way of the mission. In addition to this, she developed a perfectionist personality. The more Nightfall worked alongside Twilight, the more her respect developed into feelings for him. When Twilight was assigned Operation Strix, Nightfall wished to work with him as his wife but was unavailable at the time due to another operation. Instead, she was placed in Berlint General Hospital to work undercover as Fiona Frost, an assistant to Loid Forger, and provided him with information on his extra missions.

Campbelldon Tennis Arc
At WISE Safe House G, Sylvia Sherwood briefs Fiona on Twilight's mission next week. Sylvia is assigning Fiona to the mission, as per the latter's proposal to make it a joint operation. Sylvia tells Fiona to inform Loid of this development and to work out the plan together and warns her to ensure it does not get in the way of Operation Strix. Fiona asks about the mission's progress, and Sylvia tells her it is going slowly. Fiona apologizes and says she could have done more for the operation in the wife role had she been available earlier and wonders if she could stand in as the wife if it isn't too late. Sylvia rejects her, saying that changing wives now would draw scrutiny from Eden Academy, and the Forgers are in good standing with their neighbors, so they're keeping the family as-is. Fiona mutters that there would be no choice if the wife were to abandon the role before leaving. Sylvia warns Fiona not to be plotting something.

At the Forgers' apartment, Fiona rings the doorbell. Yor Forger opens the door, greeting Fiona, who introduces herself as Loid's co-worker. Yor apologizes and explains that Loid and Anya Forger took Bond Forger for a walk. Fiona's thoughts reveal she was aware of Loid's absence and waited for Yor to be alone. Fiona then claims she came to return a magnifying glass Anya left at the hospital; Yor thanks Fiona and invites her in. Fiona and Yor sit on the couch, Fiona sipping a hot drink. When Yor stares at Fiona, she assumes Yor thinks she is Loid's lover, then proceeds to compliment their home. Fiona is determined to remove Yor from Operation Strix and usurp her role as the wife. She tries to look for an opening but is unable with the skill Yor carries herself. Fiona decides to make Yor leave of her own will as it would be risky to remove her directly.

Fiona brings up Anya, asking if Yor doesn't tire of having to raise a child in an attempt to pressure her into giving up her role as the wife. However, Yor doesn't think so and says she and Anya have a lot of fun together. Yor wishes she was good at more things to make it easier for Loid. Fiona agrees and begins to claim that Loid frequently complains about Yor at work but is interrupted by the return of Loid, Anya, and Bond.

Loid is surprised to see Fiona and asks what she is doing there. Fiona greets Loid as Yor explains that Fiona came by to return the magnifying glass. As Loid and Fiona have a conversation, they mouth different words to communicate secretly, and Fiona states that she's here to assess the state of Operation Strix. Fiona asks Loid if walking Bond is an essential part of this operation and why Yor is not doing the errands instead. Seeing his talents wasted on playing house, she suggests they review his operational tactics, but Loid tells her it isn't her place. In her mind, Fiona proclaims her love for Loid, shocking Anya. Fiona believes she would provide far superior domestic and operational support, imagining Loid praising her abilities and deciding to marry her instead as Yor runs away crying. As Loid and Fiona stare at each other, Fiona imagines her wedding with Loid and thinks about where they'll have their honeymoon.

As it rains, the agents sit down to continue their conversation. When Yor serves everyone drinks, she gives Loid milk for his coffee. Fiona thinks Yor must be incompetent as Loid takes his coffee black but is shocked when he pours the milk into his coffee. Fiona bites at her thumbnail at the thought of Loid showing a side she doesn't know to Yor, then assumes it is part of his character as Loid Forger. Anya suddenly spills her cocoa on the table, surprising her parents. Fiona thinks about how she could have trained Anya in place of Twilight to catch the cup before it hit the table. Fiona imagines training Anya by a strict minute-by-minute schedule to maximize her knowledge and strength and transform her into a Stella Star procurement machine. Anya starts clinging to Yor and showers her with praises for being a loving parent. Fiona tries to appeal to Anya by offering imported cocoa, but Anya angrily hisses at her.

Fiona watches as the Forgers bond together and sees Loid smiling at them. Fiona has a flashback of when Loid trained her as a spy and taught her never to show her true feelings. Having observed his many disguises, she detects that this smile is at least genuine and clenches her fists. Fiona excuses herself and quickly leaves. Loid runs after Fiona to give her an umbrella and walk her to the station, but she tells him they have been assigned to partner up on the next mission. As Fiona turns towards Loid with a low expression, she thanks the rain for hiding her emotions. Fiona informs Loid that she will contact him with details at the hospital and tells him he has gone soft. She resolves to show how capable she is in the hopes that Loid will realize she is the only one fit to be his wife and walks away in the rain.

Fiona reflects on how Twilight being with his family has led him to develop inappropriate emotions and become a worse spy. Seeing Twilight become "like a knife with a chipped blade" aches her heart, but Fiona finds this new version of him adorable and endearing and still yearns for him. Because of this, she is determined to usurp the wife position from Yor.

At the hospital, Fiona details their new mission to Loid. They are to acquire the painting Lady In The Sun, worth roughly one million dalc. The painting once belonged to the late Colonel Erik Zacharis, who supposedly possessed secrets that could reignite the flames of war in a collection of documents known as the Zacharis Dossier. The Dossier is rumored to contain information about inhumane actions from both the East and the West, and the painting is the key to finding it. Not wanting to risk the Eastern government finding it before they do, they must retrieve it from Cavi Campbell, a world-renowned art collector. As the painting is beneath Campbell's mansion with tight security, Twilight asks if Nightfall has a plan, and she confirms this.

In an underground tennis court, Twilight and Nightfall show up in disguises with tennis rackets in hand. Twilight asks Nightfall if this is the best option, and she affirms this. Cavi and his underground tennis club run this competition, which is known as "Campbelldon." While the competitors are usually very skilled, the winner gets to take an item of their choice from Cavi's collection. It also rids any risks of having to try and steal the painting. The agents are announced as married couple Twain and Nafalia Foney, the identities that Nightfall registered them as. Their opponents are Walson and Bobble, a famous tennis duo that dominated the Grand Slam Circuit a decade ago. The bets are against them as men announce to the agents that they've worked hard towards perfection and will win this match.

Loid proceeds to win the round by himself without letting up any points. Walson and Bobble are shocked at their loss but decide to aim for Fiona in the next game since they haven't seen her play yet. Like Loid, she destroys them and wins the game. Afterward, their next opponents are the Bolic Brothers, who use the new drug "Oso-R" to go from thin to large, muscular men. Twilight, after seeing them, questions if this really was risk-free, and Nightfall simply tells him that they will do their best.

Loid points out the drastic difference in the brothers' appearance since the first round. Fiona informs Loid that anything goes in the tournament, from modified rackets to drugs, both of them agreeing that steroids are involved. After displaying their strength, the brothers approach the team and begin to mock Loid. Loid does not respond as they goad him, but Fiona snaps at their insults, leading her to completely dominate the match and not allow them to score any points. The Bolic Brothers lie on the ground with tennis ball marks all over their body as the announcer announces their victory. Loid questions if hitting them with every smash hit was necessary, and Fiona simply tells him her hand slipped.

Afterward, they continue to make their way through the tournament and to the finals, with Fiona making lots of flashy plays to try and impress Loid. A butler takes them to a room and informs them that the finals will begin in 20 minutes and to wait there. Once alone, the agents discuss their next opponents: Carrol and Kim Campbell, Cavi's son and daughter, respectively. The two high-schoolers have been training since early childhood, but on top of their skills, the agents must watch out for any sabotage attempts since their father runs the tournament. Fiona is confident after making it this far and believes it will be easy to beat them. Loid grabs Fiona's wrist, making her heart flutter as she wonders if he is making his move on her. However, he tells her not to push herself too hard, pointing out her bruised hand. Loid tells her that despite what she thinks, she needs to keep herself under control.

Fiona jerks her arm free and says they do not have time to waste. Loid retorts that he has heard the same from many dead comrades because "losing your cool can mean losing your life." Fiona gives in and thinks how great it is to have Loid fret over her, staring at him intensely. She then looks at the arm she jerked free and thinks about his lingering warmth and the tingling in her fingers. She then questions the tingling and then looks at the vent. Loid has also noticed and tells Fiona to hold her breath and close her eyes since a colorless and odorless gas is filling the room. Loid tries to open the door but realizes it has been locked from the outside. He considers picking the lock but considers there may be a guard outside, and it would look suspicious for "regular people" to be able to do that. Continuing their discussion in Morse code, Loid and Fiona pretend to unknowingly get caught in the trap and try to prevent themselves from taking in as much gas as possible.

As the championship match begins, Loid and Fiona are still feeling the effects of the gas. As the first set begins, the Campbell siblings use their modified rackets to win. In the second set, the Foneys tie the score with three consecutive wins. As Fiona makes a return, one of the panels on the floor drops, causing her return to go out of bounds. The spies notice this and realize there are more tricks. However, Loid is determined not to lose to such gimmicks and asks Fiona to watch his back. Nightfall stares in admiration as she thinks how this is the Twilight she fell in love with. She stands by his side and tells him that they will crush their opponents together, and in her thoughts, declares her love for him.

The Campbell siblings utilize other gimmicks against the agents, which only amount to being slight annoyances. At the start of the final set, Loid suddenly grabs Fiona and tumbles to the ground, surprising everyone, including Fiona, who asks if he is okay. Loid confirms this and explains the situation, revealing the bullet that hit him and showing it to Fiona, telling her that it is rubber and the location of their sniper. Fiona apologizes for letting this happen, but Loid reveals he anticipated this, which is why he wore a bulletproof vest under his shirt, and Fiona is amazed. Fiona suggests penalizing the staff for interference, but Loid points out that most of the tournament staff seem to be in Campbell's pocket, and any disruption to their match could risk their chances of getting the painting. However, the bullets are low-velocity, and the agents can try throwing off the sniper's aim by baiting shots as long as they can spot the signals. As the game resumes, the spies are undeterred by their opposition, even with several more tricks added to the mix, beating the Campbell siblings and winning the championship match. Carrol approaches Loid and expresses his frustration for losing, and Loid encourages the young man to improve. Watching from the side, Fiona thinks that Loid does not only strive to complete his missions but also reform his enemies, which is why she loves him.

After the game, the Foneys go through a catalog filled with all the art from Cavi's collection. Fiona picks Lady in the Sun, but Cavi appears to tell them he cannot give it to them. When questioned, Cavi explains it is due to circumstances beyond his control but promises any other item and will even give them an extra as an apology. Fiona and Loid whisper to each other, realizing that Cavi received a call from the SSS, who must have gotten the same intel and are probably on their way to pick it up as they speak. Cavi speaks up, asking if they will take his offer, and Fiona asks to see the collection in person. Granting her request, Fiona goes to a private room full of Cavi's art. Cavi asks where Loid is, and Fiona says he left to sleep off his hangover. She glances at Lady in the Sun and sees it is still in the room. Fiona then asks Cavi for a recommendation for her choice and if she can leave her bag on a nearby counter, which he allows.

The SSS agents arrive and leave after taking the painting, and Cavi's butler escorts Fiona away. The butler is Twilight in disguise, having brought a forgery of the Lady in the Sun, swapped it with the original, and hid it in Fiona's bag. Seeing the secret code, the agents agree to deliver it to HQ for analysis and high-five each other, having completed the mission successfully.

Nearing the Forger's neighborhood, Fiona offers to drive Loid all the way to his home, hoping to spend more time with him. Loid removes his disguise and reminds her that he is a happily married man that does not want anyone getting the wrong idea if they see him leaving a young lady's car; he adds that people get reported to the SSS all the time for infidelity. Fiona wonders if Loid acknowledges her skills, which would make her a more suitable wife and partner. Loid gets dropped off at a nearby park, and before he can say goodbye to Fiona, he hears Yor calling for Anya and Bond to go home.

Loid sees his family still playing at the park and takes note of it. Fiona glares at them, then steps out of her car and walks towards Yor. Fiona greets Yor, who is surprised by her presence. Loid also walks over to greet them and says Fiona gave him a ride home while she thought to stop by and say hello. Fiona looks at Yor's racket and asks if Yor plays tennis. Yor explains that she and Anya practiced with Loid the other day, and Anya proudly states that she hit many home runs. Loid thanks them for their help, and Fiona scoffs in her thoughts. Fiona believes Yor is presumptuous for believing Loid, claiming she would have helped Loid achieve further greatness. Fiona proceeds to challenge Yor to a game.

Loid asks what Fiona is doing, and she explains in code that she wants to ensure Yor is ready for the physical rigors of Operation Strix. In her thoughts, Fiona plans to crush Yor and have her relinquish her role as the mother. Loid tells Yor that she does not have to accept, but Yor accepts Fiona's challenge. Before starting their game, Fiona tells Yor to come at her with everything she has. Loid tries warning Fiona but gets told to step back. Yor agrees with Fiona's statement and decides to go all out, making a powerful swing as she serves. However, Yor seemingly misses, and the ball drops to the ground. Fiona scoffs at this but sees the ball slice up into small pieces. Fiona is stunned and tries to process what just happened, while Yor says she will try again. Yor makes her second serve, which moves faster than sound and in a perfectly straight line. Fiona realizes this might kill her, and she tries her best to return the ball but struggles to push it forward. She thinks about how her love for Twilight cannot lose to Yor, who stands in the way of her ambition. Fiona ultimately fails, and the ball breaks through her racket.

Fiona falls to the ground, shocked by her utter defeat. Yor rushes to Fiona, asking if she is okay, while Loid thinks about how he warned Fiona. Fiona declares Yor the victor for now but will one day challenge her to a revenge match. Fiona tells Yor to enjoy her life until then before quickly driving off and, in tears, declares that she will never give up. Afterward, Fiona trains in the mountains to train her swing speed. Swinging a stick with a large rock tied to it, Fiona roars while the wildlife watches from the side in fear.

WISE Arc
Sylvia briefs Fiona on a man named Sergei Ostosky, an executive on the economics committee who is unlawfully restricting strawberry exports to Westalis, causing a national strawberry shortage. As a result, there were no strawberries on Foreign Minister Brantz's birthday cake, and he went into a rage. Sylvia assigns Fiona a mission to deal with the problem before it causes a diplomatic crisis.

Fiona approaches Loid at Berlint General Hospital, asking for someone capable of forging a state seal for a fake export license. Loid decides to direct Fiona to one of his assets with the connections to do so. As he leaves to talk with some staff, Fiona stares at him from behind with a lovesick expression in her eyes and resolves to complete the mission for his sake.

In an alleyway, Fiona heads down a flight of stairs to the location of Twilight's asset. As she approaches the door, she sees a button and a note stating to press the button for "service." Suspicious, she uses a pen to press the button, and it is revealed to be an electrified trap. She scoffs at the childish trap and enters before a dusty chalkboard eraser falls from above. As Fiona goes through, she encounters several amateur-level traps and riddles. Finally, she comes to a door at the end, where she is greeted by a man with a black bag over his head aiming his gun at her. Fiona greets the man with Twilight's code phrase, and he removes his bag revealing him to be Franky Franklin. Franky tries to flirt with her jokingly, and she almost leaves out of exasperation.

Fiona names her request for a forged official seal, and Franky tries to get more details from her, saying he will get it from a friend of his. Fiona is unwilling to trust him and tries to get him to introduce his friend to her directly, threatening to have him incarcerated. She eventually acquiesces when he reminds her that she will not be able to meet with the counterfeiter without him, and he contacts his friend via the radio as a secret caller.

Fiona and Franky are waiting outside a bar where they arranged to meet with the counterfeiter. Fiona attempts to enter, but Franky stops her and convinces her to wear a disguise before entering. They change into disguises suitable for a club, pretending to be a couple. Franky is excited to be on a "date" with Fiona, who is wholly unenthused about the situation. As they enter, they are stopped by the bouncer until Franky reveals his identity. At the club, Franky greets his many friends, showing off his "girlfriend." Eventually, Fiona reaches her limit and threatens to kill him unless he stops. Franky apologizes before noticing the presence of his counterfeiter friend downstairs, and they approach him. Franky tries to greet him, but Fiona interrupts and gets straight to the point with her offer. She tosses a paper with her deal at him, but he throws it away upon seeing it and the deadline, walking away.

Fiona and Franky continue to follow him outside. Fiona points out two members of the SSS tailing them. The counterfeiter is shocked and accuses Franky of being careless. Fiona suggests it was his new clients that made a mistake. The counterfeiter tries to make a run for it but is too late to notice a man around the corner. Before he can get hit, Fiona pushes him down and kicks the man in the face, incapacitating him.

Fiona grabs the counterfeiter as they run and suggests he take her offer as repayment for saving him from the SSS. As they pass a corner, Fiona expertly throws another man waiting behind the corner with a knife. The counterfeiter is speechless at her skill, and Franky reassures him that he can trust Fiona. Another man shoots at Fiona, and Franky throws himself at Fiona to get her out of the way while she throws a knife at the shooter.

Fiona tries to get them to another place to hide from the SSS, but Franky displays his knowledge of the area and suggests using a tunnel path instead. Later, Fiona meets with Franky at his tobacco stand. He hands her a copy of the newspaper, along with the forged papers she asked for. Franky asks if she was the one who called the SSS men on them, but she feigns ignorance. Fiona asks Franky if he has connections to fine art forgers and safecrackers, suggesting she will return to him with another job. Franky looks briefly moved but refuses to work with her, stating that he will lose his friends with her methods.

Friendship Schemes Arc
At Berlint General Hospital, Loid gets swarmed by affection from the staff and patients. Watching from a corner, Fiona thinks about how perfect Twilight is; she contemplates getting rid of the women flocking to him, but she reminds herself not to interfere with the mission. She then notices a man watching Loid from a doorway while gritting his teeth. Loid calls Fiona to his office to discuss his new plan: to interact with any patients connected to Melinda Desmond, Donovan's wife. He explains to Fiona that Yor managed to join Melinda's social circle and how he wants to extract any information from them. Fiona proposes to be his wife to help, but Loid denies her as he needs her for a support role, which disappoints her. Fiona says there may be some patients but believes they will not let Loid see them. Loid assumes it is because of his lack of reputation, but Fiona corrects that their director will not assign him any patients out of personal spite.

Loid is confused, so Fiona explains that the director, Gerald Gorey, looks at Loid with envy, which deepens the more his standing rises. Gerald built his position through careful networking and values status and reputation. Because of this, he has grown jealous of Loid's rising popularity in the hospital, despite Loid taking great pains to get on his good side. Fiona says all exams for VIP patients are personally assigned by Gerald, meaning Loid will have to deal with him sooner or later. While Fiona exits the office and thinks about how long Twilight spoke to her, Gerald watches from a corner. Believing that Loid is going after Fiona, whom he has feelings for, he vows to make Loid a pariah in the hospital.

Gerald starts trying to get Loid disliked by the hospital staff, which goes terribly in his favor. He even writes a poorly written letter pretending to be Loid and asks for a meetup with Fiona. He hopes it will get Loid in trouble for infidelity and help him get closer to Fiona. Fiona is exasperated at having to deal with the obvious forgery and crumples it up. She approaches Loid afterward and suggests getting rid of Gerald, but Loid says they will keep putting up with him. Frustrated, Gerald makes his last resort move, calling the State Security Service and reporting Loid as a spy.

Disguised as SSS agents, Fiona and Franky enter the hospital to confirm Gerald's report. Gerald shows them Loid and the files he used to back his claim. The two pretend to arrest Loid, cornering him when alone and cuffing him. While Loid and Franky banter, Fiona reminds them that Gerald is watching, and they resume their little act. Loid looks at the files, and he and Franky pinpoint the source back to Gerald, quickly turning the tables. Gerald tries to deny framing Loid, but Franky pulls out a fake gun and demands his name. After Gerald reveals his name, Fiona says he is on the hospital's surveillance list, and Franky begins citing his misdeeds, provided by guesses from Fiona and intel from Loid.

Fiona decides that the one they should be taking in instead is Gerald, who cries out for her when he gets handcuffed, and she wonders why. Before Gerald gets taken away, Loid stops the faux officers to defend Gerald. He says that despite his misconduct, Gerald would never sell out his country, is more popular than him, and is a great team leader. With fake tears, Loid says Gerald is the hospital's greatest treasure and asks to be arrested in his place. Gerald is touched by this act, while Fiona thinks about harvesting Twilight's tears, even if they are fake ones. Fiona and Franky choose to let him go and take their leave shortly after. Gerald is forever grateful to Loid, who offers to help lighten his load with things such as the VIP exams. Outside, Fiona and Franky decide not to change out of their costumes, Fiona because Twilight made her the costume, and Franky because he likes how cool he looks.

Red Circus Arc
Thomas Austin, a victim of the recent bus hijacking incident with the Red Circus group, seeks Loid's help with nightmares he has been having recently. Observing the session outside the room, Fiona notes inconsistencies in the man's words and body language. After the session, Fiona enters and asks if Thomas is lying, but Loid is uncertain and asks her to look into it. Fiona obliges while also counting their brief interaction time.

Fiona later gives Loid the investigative report on Thomas, which helps him realize that Thomas' wife is, in fact, his source of stress. While offering tips on resolving their relationship, Loid tells Thomas to observe everything about his partner, and Fiona, eavesdropping from behind the door, remarks that no normal person can do what Twilight does. After trying some talk therapy, Loid is exhausted, while Fiona muses that she would never let their relationship sour if she was his wife.