Aoki, a member of the professional swimming 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 witnesses this and uses this as a joke to blackmail Aoki and seduce 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...