Episode 20

Henry Henderson assigns his class a social studies project: investigate an occupation, interview someone in it, and present a report on Friday. Anya first approaches Yor, who silently daydreams an entire field trip through her assassin work, complete with polite kill techniques, anatomy lessons, and an imagined Anya drenched in blood. Having read every second of the fantasy, Anya switches to Loid's job instead.

Two days later Loid escorts a detective-costumed Anya through Berlint General Hospital, where he practices psychiatry. His spoken answers stay wholesome, but Anya transcribes the thoughts underneath: the hospital was chosen because political, industrial, and military figures pass through it, contacts reduce suspicion, and the true difficulty of the work is keeping it subordinate to his mission. Staff members coddle her and gush about how adored Loid is. In a corridor, Fiona Frost makes her first appearance, slipping Loid documents that conceal a new assignment and noting with surprise that a child can rattle Twilight. Left alone in a consultation room, Anya pulls the hidden lever Loid's thoughts revealed and descends his emergency escape route. Through a vent she eavesdrops on researchers debating the neuroscience of paranormal perception, traps her foot under a pipe, and fills the duct with struggling noises the men take for a genuine haunting. She scrambles back just in time, and Loid misreads her chaotic sand-table doodling as adoption stress, blaming his own parenting. On Friday her class report blends psychiatry with spy details and claims her father punches and kicks patients, a description of Yor's garbled "concussive therapy" story. A summoned Loid smooth-talks the school out of concern.

The anime-original second half begins with a Spy Wars scene inspiring Anya to stage a coded rendezvous. Since her handwriting would render any cipher unreadable, Yor transcribes the copies, which go to Bond, the neighbors, Franky, Becky, and Damian, who crumples his instantly. Franky, smelling perfume on the page, decides a beautiful woman has sent him a love letter, cracks the cipher overnight, and stands at the meeting point in formal wear clutching roses. Anya sleeps straight through the appointed hour after Bond shuts off her ringing alarm.

Fiona Frost debuts, passing Loid a disguised mission at the hospital and remarking on Anya's ability to fluster him.

Anya explores the concealed escape passage beneath Loid's consultation room and unintentionally converts a panel of doctors into ghost believers.

Loid interprets Anya's scrambled sand table as psychological distress from her adoption and resolves to be more attentive.

Anya's classroom report exposes fragments of Loid's double life, forcing him to defuse a school summons with practiced equivocation; her secret-code experiment ends with Franky alone at the rendezvous.

The first half adapts Chapter 29 and opens the Campbelldon Tennis Arc; "Decipher the Perplexing Code" is exclusive to the anime. The episode aired in Japan on November 19, 2022.

Franky's hideout debuts here far ahead of its manga introduction in Chapter 60, and the mailman receiving Anya's code is the same one from Episode 1's ending. Blood in Yor's imagination sequence is tinted pink rather than red, and Anya's detective outfit loses most of the manga's checkered pattern.

Around the eight-minute mark a shadow lingers at a corner while staff praise Loid, likely Fiona, though possibly Gerald Gorey. The classmates' reactions to Anya's report were never shown in the manga.