One year after becoming a teacher, a young adult colleague joins senior teachers Ryo and Nami to preview a school-trip destination. When they arrive, they discover that only one room was booked. Feeling responsible, he runs around inspecting the property and accidentally encounters both women bathing during his final check. They forgive his mistake, but the sight of their seductive naked bodies and the drinks that follow bring the three closer. Soon a dreamlike night begins, with both experienced teachers draining him again and again until dawn—ten times in all.