The episode starts off with a blue-haired girl running from a red-haired girl chasing her and firing with a loaded pistol. Later, the same blue-haired girl wakes up in bed shocked to discover her own body, and even weirder sees a tiger doll thing that looks as if it were in the middle of seppuku. The doll's name is Harakiri Tora, and it tells the girl, Natsuru, that she was chosen to become a Kämpfer. After freaking out for a bit, Natsuru wants to go back to sleep, and the doll helps by jumping on her chest. When Natsuru wakes up, he's a boy again.
Natsuru tries to catch the bus with his crush, Sakura, but on the way to school he runs into the same red-haired chick with the pistol from before. Seeing his bracelet glowing, he disappears from the scene and turns back into a girl with a brief magical girl henshin sequence. After a brief fight, Natsuru finds out s/he can throw fireballs at people, and Akane decides to leave. Eventually, arriving at school as a guy, Natsuru runs into Akane again, except this time she's a shy, bespectacled librarian who seems to apologetically find lewd double-entendres in everything she says. She explains that Kämpfers carry one of three weapons: Schwert (sword), Gewehr (gun) or Zauber (magic), kind of like rock-paper-scissors, except no weapon type appears to have a natural advantage over another.
The next day, Natsuru runs into Sakura again, thinking that she finally wants to confess her love to him. Instead, she asks Natsuru to introduce her to the female version of himself, without knowing that they are actually the same person. He decides to ask Akane for advice, but as the two of them are talking in the school's library they find themselves under attack by another Kämpfer with a chain-blade weapon that cuts through the bookshelves like paper. After one attack, Sakura is shown standing in the rubble. Thinking she's the attacker, the transformed Akane points her gun in Sakura's direction and fires as the episode ends.