Kakeru, a former elite runner at high school, is chased for stealing food. He is saved by Kansei University student Haiji, who is also a runner. Haiji persuades Kakeru to live in the old apartment "Chikuseisou" where he plans to team up with fellow residents to enter Hakone Ekiden Marathon, one of the most prominent university races in Japan. Kakeru soon finds out that all of the residents except for Haiji and himself are complete novices.

Mizuki Hijiri, is a high school girl who just transferred schools. At her new school, she has a fateful encounter with boys suffering from chuunibyou (adolescent delusions of grandeur). There is Noda who dreams of becoming a hero, the tragically handsome otaku Takashima who only likes 2D girls, Nakamura the supposedly "reincarnated" angel or devil (he can't decide which), and the self-professed string-puller Tsukumo.

Inspired by a small-statured pro volleyball player, Shouyou Hinata creates a volleyball team in his last year of middle school. Unfortunately the team is matched up against the "King of the Court" Tobio Kageyama's team in their first tournament and inevitably lose. After the crushing defeat, Hinata vows to surpass Kageyama. After entering high school, Hinata joins the volleyball team only to find that Tobio has also joined.

After a long day, high schooler Shintaro Tokumitsu's plans for relaxing in his studio apartment take a turn when he discovers an angel on his balcony. The divine girl, Towa, reveals she's there to study humanity, and yet, despite his skepticism, he agrees to put her up. Prepare for the most heavenly and high jinks roommate experience of all time!