At Morimori Academy, a private all-boys boarding school hidden deep in the mountains, transfer student Takashi Toono struggles to fit in. The friendly and outgoing Kyousuke Yaguchi becomes his first friend, but the school's mandatory club policy forces Toono to choose an activity. Opting for the low-key Photography Club, he soon learns its shocking true nature: it's the "Yarichin Bitch Club," a group of sexually liberated members who offer their bodies to relieve the frustrations of other students.

Newcomers like Toono and fellow transfer student Yuu Kashima face a strict monthly sex quota. Failure means the club will forcibly take their virginity in a gang scenario. As Toono navigates this mortifying situation alongside Yaguchi and Kashima, the club deals with intense encounters, hidden secrets, emotional confessions, and even a dangerous stalker targeting one of the members.

Blending explicit yaoi action with awkward school life, humor, and budding relationships, Yarichin Bitch Club explores desire, pressure, and unexpected bonds in a hyper-sexualized all-male environment. The story follows the first-years' desperate attempts to meet quotas while the eccentric upperclassmen indulge freely.