The Island of Treachery

Hana leads her students to an uninhabited island once used as a village training ground for an overnight outdoor lesson, warning them the neglected terrain could be dangerous. The children thank her for organising the trip to make up for the festival. Trouble starts when Mimi's ninken Kikuchiyo is injured by a trap, and Sōsha repeats a rumour that a killer missing-nin lives on the island. Kawaki grows suspicious that the trap looks recent and that nobody could stay hidden there for long, though Hana explains people have long fled to the island, some unaware the war ended. Their food then vanishes, and with the ship not returning until the next day, the students set up camp and forage while Osuka finds edible plants using skills from a stint living on a mountain. Kae assembles a flower arrangement as a gift for Hana. Privately, Hana reflects that she would have killed them all if a mission were not still binding her.

When Neon's scouting drone is knocked out of the sky, the group suspects the missing-nin, unaware Hana is watching from hiding. That night Kawaki tells Kae the trap had been baited with Kikuchiyo's food, marking the ninken as the intended target. Kae reveals she will return to the Land of Bamboo once the class ends. Examining the drone, Himawari finds its blades cleanly sliced and the damage too severe for the fall, so the group reviews its recorded footage. Kawaki spots Wind Release flower petals in the corner of the frame just before the recording cuts, evidence that points straight at Hana. Discovering Kae's discarded arrangement, the two confront Hana as she tries to lead the girl away. Hana throws down a smoke bomb, flees with Kae, and fights off Kawaki and Himawari with her Wind Release before reaching a bridge, where she appears to slash Kae with a kunai as the two watch in horror.

Hana takes the Academy class to a deserted island for an overnight lesson that quickly fills with warning signs: a fresh trap that wounds Kikuchiyo, vanished supplies, and a sabotaged drone. Kawaki's growing distrust and Himawari's analysis of the drone footage reveal Wind Release petals that implicate Hana herself as the hidden threat.

Cornered, Hana drops her cover, uses a smoke bomb to escape with Kae, and repels the two students with Wind Release. At a bridge she seemingly cuts down Kae, leaving Kawaki and Himawari stunned. Kae also confides that she intends to go back to the Land of Bamboo after the trip.

The entry belongs to the Kawaki and Himawari Academy Arc and builds tension around Hana Kaka, whose true role as an assassin surfaces over the course of the trip. Details such as Osuka's mountain survival background and Kae's plan to leave for the Land of Bamboo add to the ensemble of Academy classmates featured throughout the episode. The cliffhanger apparent killing of Kae leaves her fate deliberately unresolved.