WISE agent Fiona Frost, AKA Nightfall (voiced by Sakura Ayane in her lower meter) could just as easily be named Snowfall, seeing as she’s outwardly as chilly as Yor is warm. When Handler tells her she’ll be working on a joint mission with Twilight, Fiona jumps at the chance.
She considers it an opportunity to speed up and improve Operation Strix by getting rid of his fake wife, a position she would have occupied had she not been busy on another mission when Strix began. Fiona is met at the door by guileless Yor, who apparently doesn’t feel any killing intent in Loid’s co-worker from the hospital, even as Fiona’s resting face is a piecing dagger stare
When she realizes that Yor considers being Anya’s mom to be fun, she changes her tack, ready to exploit Yor’s feelings of being a subpar wife, but Loid and Anya return home from walking Bond. No matter how good Fiona’s poker face is, Anya can read her mind, and she’s petrified to learn the extent of Fiona’s infatuation with her Papa. It’s way worse than Becky!
The contrast between the lovey-dovey Inner and frigid Outer Fionas makes for good laughs, as does the secret conversation-via-mouth-movements that she and Loid make while sounding like they’re exchanging mindless small talk. As Loid, Yor, and Anya interact, Fiona is constantly demanding that she and Yor switch in her head, and Anya can hear her.
Turns out Yor was paying attention to Fiona talking about Loid complaining at work, and even though Fiona didn’t get to actually specify anything, the mere mention of him complaining has Yor acrobatically leaping to the conclusion that Fiona is a potential replacement wife, no mind-reading necessary.
It’s when Anya semi-accidentally spills cocoa, and she hears Inner Fiona talking about how ruthlessly she’d whip Anya into an efficiently Stella-winning machine, that Anya runs tearfully to Yor’s side, asserting that she is the one, only, and best Mama she could have. This in turn spurs Yor to promising to Loid that she’ll do better, even though from his perspective she’s already been doing fine.
When she sees Loid’s fake smile, Fiona is heartened, as it means that at the end of the day this is all an act. And yet, at the same time, she can see some of the truth leaking through that fake smile, and the genuine peace and happiness Loid is experiencing with Yor and Anya is just too much, and Fiona takes her leave.
Loid chases her down with an umbrella, which she declines, while thanking the heavy rain for hiding her face full of heartbreak and anguish. Inside, she maintains that she’s the only wife worthy of her beloved senpai, while outside she negs Loid, telling him the new “softer” Twilight better not impede their joint mission.
Fiona is a stylish and welcome addition to the cast; someone who is actively trying to steal Loid while having no idea how to do so, someone with contrasting inner-outer personalities off which Anya can bounce, and a hint of genuine pathos for someone whose fated role by Loid’s side was usurped due to bad timing.
The final fifth of the episode is a little vignette in which Bond is suddenly jealous of her stuffed Mr. Penguin, and assaults it in the night. Loid eventually mends the doll (after Yor utterly failed) and notes that his “scars” are badges of honor for a veteran penguin spy.
A contrite bond offers peace peanuts to Anya, who forgives him, apologizes for saying she hated him, and enacts a peace treaty between him and Mr. Penguin. It’s slight and sweet—almost to the point of cloying—but does make for a nice parallel for the East-West conflict (would that it could be solved so easily) and reminds us that even precognitive flooffers can get jealous.