Uno Seiya, a lonely student with a passion for stargazing, finds his quiet life disrupted when he meets Momota Kaedeko, a transfer student with a daring exhibitionist streak. After a chance encounter leaves them bonded by a shared sense of isolation, the two engage in a series of risky sexual escapades around their school. However, their secret is discovered by the puritanical class representative, Ikkaku Rose, who attempts to intervene in their unconventional relationship through a series of provocative trials.
As sexual tensions rise at school, the Class Rep explores her hidden desires with Seiya, while Ikkaku finds an unexpected partner in Inuta. During a summer seaside camp, the group grapples with their complicated feelings and secret encounters, culminating in a stargazing event where Seiya seeks a deeper emotional connection with his friends.