Princess Principal/Recap/S1/E10 Case 22 Comfort Comrade

Quoting from Wikipedia: "Ange, Dorothy, and Beatrice are sent on a mission to steal secret documents from the First Lord of the Admiralty. They gain assistance from the inside by another Commonwealth agent, Prefect, who was trained in the same class as Ange and Dorothy. During the mission, Beatrice learns that Prefect always ended up being second best to Ange, and the two don't get along because of that rivalry. The mission ends up being a success, and the group celebrates at a pub. Ange and Beatrice leave early while Prefect and Dorothy reminisce about their final exam where, believing that they had failed the exam, Dorothy took Prefect to a local carnival to have some fun. Meanwhile, Ange takes Beatrice to Prefect's room, revealing that Control suspects Prefect is a double agent. Ange deliberately triggers one of Prefect's traps, causing her to flee and confirming the team's suspicions. Prefect is able to evade Ange and reach a train, but Dorothy catches up to her and holds her at gunpoint. Prefect admits that she was poisoned and forced to work for the enemy in return for the cure, and that the woman she looked up the most to and wished to be was in fact Dorothy, not Ange. Prefect then commits suicide so as to spare Dorothy the task of executing her. Ange and Dorothy return to Control to report their success when they discover that L has been replaced by a new superior, General. General congratulates them and then tasks them with a new mission: assassinate Princess."


 * Anyone Can Die:
 * Discussed: Of the dozens of girls who trained to become spies during the flashback, it's mentioned that only Ange, Dorothy, and Prefect survived.
 * Played Straight: Prefect doesn't survive the episode.
 * Spy School: In a flashback we see some of Ange and Dorothy's training by the Commonwealth, along with dozens of other girls being groomed as spies, in a school that appears to be based on the Real Life Special Operations Executive "Camp X".