The story of Harenochi Munasawagi does not start in a very original way: the protagonist is a high-school boy named Kazuhiko, who is - surprise! - permanently horny, displaying his "affections" at any given opportunity to anyone young and female, including even his childhood friend Chihiro. But while the focus on the story is on Kazuhiko and his quest for physical intimacy (which often results in girls getting angry and beating him up), there are other rather disturbing elements that come into play later - in particular, bunny-like demons who share Kazuhiko's passion for the opposite sex...
The protagonist, Kazuhiko Saotome, serves as the student council president at Hakuyo Academy. Despite his leadership position, he is notorious for his mischievous behavior and frequent involvement in problematic situations. One day, a series of underwear thefts occur within the school premises, prompting Kazuhiko to investigate the incidents. Throughout his inquiry, he interacts with various female students and faculty members, each with unique personalities and backgrounds, leading to comedic and romantic encounters.