High school student Nanahoshi Kiseki possesses extraordinary luck, but his ordinary life is shattered when his younger sister, Mahoro, has her lucky panties stolen by a mysterious strip gambler known as Joker. Determined to get them back, Kiseki disguises himself as a beautiful girl, adopting the alias Nanahoshi Mikuru, and infiltrates the school's Gambling Club, a club composed entirely of female members. The club's activities revolve around high-stakes strip gambling, where participants wager their clothing in a variety of games. As Mikuru, Kiseki must navigate the perilous world of strip gambling while keeping his male identity a secret. The club's daily life includes new members joining, signature events, and escalating challenges. As the story progresses, the mystery surrounding Joker deepens, leading to a climactic revelation of Joker's true identity. The series blends comedy, cross-dressing hijinks, and gambling tension, following Kiseki's desperate mission to recover his sister's panties while avoiding exposure.