In this world, certain girls are gifted with supernatural abilities to drown other girls in sexual pleasure. Succumancers - as the beautiful users of this power is called - fight for fame and glory in intense battles that involve bringing their opponents to climax. Amanotsukasa Yoshino enrolls in the prestigious National Ishtar Women's Academy with the goal to win the National Succumancer Tournament and become the #1 succumancer ever. But how can she do it with ability level F, the lowest score in the whole school?