Upon entering Ebisugawa High School, Itsuki Noya goes to the 'Tenmon' club, believing it to be the astronomy club, and wishes to join. However, the club president, Kyōko Todayama, decides to first put Itsuki through some bizarre tests, which seemingly have nothing to do with astronomy. After the tests are more or less deemed worthless, Itsuki is made a member, saving the club from being abolished.