Adult track-team member Yui is told that her place in an upcoming competition is uncertain, so she signs up for an intensive training camp. When she arrives, she discovers that only she and the coach are there. With no other teammates around, he gropes her while she holds an air-chair squat. Knowing she cannot resist without dropping, he claims that pressing the head of his cock against her vaginal opening will help her endure. Yui desperately tries to keep her hips raised, but as her strength gives out, he gradually pushes one centimeter, then two, inside her. The two-night, three-day camp escalates into deep pounding, piston-like cowgirl riding, and ten ejaculations.