Mihama Academy is a prison-like school. It is home to five female students who each have their own reasons. One day, Yuuji the institute's first male student arrives and throws the orderly rhythm of Mihama off balance.

An astronomy club gets caught up in a bizarre series of events at an old school building while trying to unravel the circumstances revolving around the sudden appearance of a mysterious transfer student named Yui.

Recorder and Randsell is the story of the siblings Atsushi, a young school boy who looks like a grown man, and his sister Atsumi in high school who looks like a small kid. It follows their comical and absurd life.