Yu-yu Kondou, a 15-year-old boy with a shy and timid personality, is constantly subjected to his zany sisters' unrealistic demands. Fed up, he runs away from home when they coerce him into crossdressing for their amusement. Unexpectedly, he meets a genial girl named Megumi Ookura who introduces him to a clique of avid Cardfight Vanguard gamers called Team Blackout. As Yu-yu grows closer to Danji Momoyama, Zakusa Ishigame, Tomari Seto, and Megumi, he discovers an exhilarating world he never thought possible. Thanks to his new friends, Yu-yu is able to step outside his comfort zone and embrace new experiences.