G-Men follows the story of Shouta Kadomatsu, who transfers to an all boys school in hopes of finding a girlfriend, as the school is surrounded by four all-girls schools. A rumor at his school states that there is a 120% of losing your virginity before graduation, however, Shouta finds himself in class G, which is the lowest ranked class in the entire school, and is filled with delinquents, nerds and losers – the types of guys girls aren’t interested in.