A guy wakes up as a girl and has to fight other magical girls while his lesbian best friend suddenly wants him. The show knows exactly what it is, pure chaos wrapped in beautiful animation and voice acting that makes every line land harder than the premise has any right to. No plot arrives to ruin the joke; it's 12 episodes of "what fresh hell is this" comedic timing, and that's the entire point.
Natsuru wakes up as a girl. Not gradually. Not metaphorically. He's simply a woman now, and a talking stuffed tiger shows up to explain that he's a Kampfer: a magical fighter destined to battle other Kampfers in female form. The catch is that his real body gets locked away whenever he transforms, meaning he's stuck living as a girl at school while his actual self sits at home, completely trapped. The situation spirals immediately. His childhood friend Kaede, who also happens to be female, discovers his secret and develops feelings for his new body. His school separates boys and girls into different sections, so he's somehow enrolled in both. Rumors spread that he's dating himself. Meanwhile, other Kampfers emerge around campus, and Natsuru can't tell if they want to fight him or ask him out, which sometimes seems like the same thing. Between managing his double life, defending himself in combat, and navigating unexpected romantic attention from multiple directions, Natsuru's ordinary high school experience becomes anything but.