In "Nightfall," Sylvia Sherwood, also known as the Handler, calls Fiona Frost, also known as Nightfall, to her office. The episode 20 tale "Investigate the General Hospital" introduces Fiona as the Berlint General Hospital clerk. Sylvia gives Nightfall the task of collaborating with Loid Forger, a.k.a. Twilight, after deciding that safety measures must be made for a brand-new independent mission.
Nightfall laments not being able to participate in Operation Strix during her talk with Sylvia because she believes Twilight would have been better off with her as his bride. Sylvia objects, claiming that it is in their best interests for Twilight to be married to Yor, an Ostanian who lives nearby. She also emphasizes how odd Loid's unexpected remarriage would appear to the Eden Academy. She instructs Nightfall to concentrate on the tasks that have been given to her as a result. Asserting that Nightfall is the kind of spy who isn't afraid to get her hands dirty to achieve her goals, Sylvia urges Nightfall not to have any ideas when she inquires about the prospect of Yor "retiring" her role as Loid's wife.
What did Nightfall say?
Yor welcomes Nightfall as she pays a visit to the Forger home in the role of Fiona. As a pretext for "inspecting" Yor, Fiona identifies herself as a coworker of Loid and gives Anya's magnifying lens from Episode 20 back. She informs Fiona that her husband isn't at home and offers to let her remain inside their apartment until he gets back. Yor extends a coffee invitation to Fiona, who accepts it.
Yor and Fiona are alone together and starting to examine one other. Yor is enthralled by Fiona's attractiveness, and the latter considers how she would get rid of Yor on her own if she jeopardizes Operation Strix. Additionally, Fiona muses on the likelihood that Yor views her as a mistress and decides she's not wholly mistaken as she not entirely wrong as she intends to steal her role as Loid's wife from her the moment she gets the chance.
Since killing Yor would attract unwanted attention, Fiona reasons she'll need to figure out a way to get her to leave Loid on her own, hinting that she intends to plant the seeds of jealousy. To that end, she asks Yor about her responsibilities as a mother raising Anya, trying to get her to admit the workload is unmanageable. Yor, however, surprises Fiona when she admits Anya is a joy to work with. Unfortunately, Yor unwittingly validates Fiona's own concerns when she admits Loid does the bulk of the housework because she's sorely lacking in a lot of crucial homemaking skills.
After Yor admits her flaws, Fiona attempts to further plant the seeds of self-doubt by telling her what "flaws" have been "confessed" to her by Loid, but she is interrupted by the latter's timely arrival. Loid is naturally surprised to see his colleague in his apartment and attempts to learn her intentions by speaking to her in code. Fiona states that she was just checking in on the progress of Operation Strix. She then gets to the heart of why she's there and inquires about why Yor is not fulfilling her role as his wife. Loid is naturally suspicious of Fiona's implications and is not keen on involving her in Operation Strix.
As Anya observes the conversation between Loid and Fiona, she notices that the two spies don't get along and wonders if she's an evil spy. She then attempts to learn Fiona's ulterior motives by reading her mind, only to discover the latter is actually in love with Loid and is jealous of her adoptive mother Yor. Upon reading her mind further, Anya realizes she wants to occupy Yor's role as Loid's wife, not just for the mission but also in real life. At some point, Fiona stopped conversing with Loid and gets lost in thought, which makes Loid a little concerned. Yor then breaks the ice by inviting them both to drink coffee.
While boiling some hot water for coffee, Yor thinks about what Fiona attempted to tell her earlier. It starts to dawn on Yor that Loid is secretly unsatisfied with her and begins to internally panic at the thought of him leaving her for Fiona. Rather than act on those feelings, however, Yor proceeds with serving coffee to both her husband and guest and hot cocoa for Anya. When Fiona observes Yor offering Loid milk for his coffee, Fiona recalls how Twilight prefers his coffee black and is surprised to see him pouring milk into his coffee. She then rationalizes that he's only adding the milk as part of his role as Loid Forger and that he hasn't changed at all.
Anya accidently spills her hot cocoa on the coffee table while amusing herself on the opposite side of it with the idea that Fiona is envious of Yor. When Yor promptly cleans up after her, Fiona considers how Anya wouldn't behave so carelessly if she were in charge of her. She then considers how she would personally punish Anya in order to make her a "stronger daughter," which involves abusing her.
Anya, who can still read minds, finds Fiona's ways of raising children terrifying and clings to Yor for support. She then discreetly tells Fiona that she is content with her family and does not need a new mother. This prompts Yor to vow Loid that she will keep up the action. her best in a fit of anxiety. Loid, however, validates Yor by telling her she's already a hard worker, which is why Anya is happy with her, and won't ask more of her. Fiona, however, doesn't believe in the sincerity of his actions or words as she knows he's an outstanding performer -- not just because she's seen him work, but also because he personally trained her.
After a somewhat long observation of Loid's interaction with Yor, Fiona decides to make her exit by excusing herself as needing to buy some potatoes. Loid, however, knows there's a lot more she's not saying and decides to go after her. After catching up with Fiona in the rain, she finally reveals to him the new mission that's been assigned to them both by their handler, Sylvia. Loid states that she needed to say this from the get-go. Fiona tells him she'll reveal the details of their new mission at the hospital and requests that he not hold her back, having lost his edge from playing house. She then departs with the thought of wanting to be by Twilight's side, even if it's just as a pretend wife, but needs to conceal these feelings for the sake of their work.
In "First Fit of Jealousy," Anya watches one of her favorite anime with Bond, but in the episode they're watching, one of her favorite characters -- the penguin character -- is killed in action. The character's death traumatizes Anya, who then decides to sleep with her penguin plushie that night. When she wakes up the next morning, however, she's devastated to find the penguin plushie has been ripped to shreds.
Anya instantly accuses Bond when Loid says the rips resemble bites and scratches. Bond then confirms her suspicions when he considers the reason he destroyed the plushie: he was envious of the attention Anya was paying it. Anya becomes furious and says she hates Bond as a result, ruining the beautiful white dog. Anya cries aloud as Yor makes a horrible attempt at sewing the plushie together. Anya declines Loid's offer to purchase her a new penguin since the one she already has is significant to her and was a gift from her adoptive father at the aquarium.
While Loid stitches the penguin back up, Bond goes into the kitchen to get Anya some peanuts as a peace offering. After Loid finishes stitching the penguin, Anya complains that he looks like Frankensteins' monster, but Loid states it couldn't be helped. He then gets Anya to think of his scars as "battle scars" it acquired for fighting the good fight. Bond then apologizes to Anya for destroying the penguin with a bag of peanuts, and -- with some persuasion from Loid -- Anya accepts the dog's apology, and she herself apologizes for telling him she hates him.
Based on the popular manga series by Tatsuya Endo, new episodes of Spy x Family stream every Saturday on Crunchyroll.