Airu Ooshima is a girl living alone with her father. After her mother's sudden passing, the savings left behind have been completely drained, and her lazy, unmotivated father has run out of options—until he comes up with the bizarre business idea "Mega-Tits Little Sister Paradise," renting out his own daughter. Though Airu has no special skills, she inherited her mother's massive, attention-grabbing breasts, an asset that turns heads wherever she goes. Can she use her busty charm to make the business a success?