Aoki, a member of the professional swim team, was dating his senior, Himori. While on a moving bus, Aoki secretly gives oral service to her boyfriend, who is in a slump, to cheer him up. However, his teammate Shiomi, who witnessed this, blackmails Aoki and seduces him. Shiomi, who is feeling better, starts acting next to Aoki who is tired and sleeping on the bus and drives Aoki crazy with pleasure...