Natsuno Hanabi is returning to her home in the countryside for the first time in six years to attend high school. She was expecting to live in the luxurious designer-condo-style dormitory Tachibana Manor... but due to an error, she ends up in the run-down apartment building Tachibana House. On her very first day there, she encounters a mysterious naked girl, witnesses an older girl in an embarrassing moment, and even ends up face-to-face with an embarrassing view of her close friend from childhood. And... she doesn't see any of this as "lucky" at all, okay?!