During a club training camp, a female college student with G-cup or larger breasts is the target this time. Ria-san is the vice-captain of the club, a third-year student in the tennis club at T Gakuin University. What happens when a man and woman in such a relationship bathe together almost naked? The younger male junior can't help but get an erection when he sees that the senior female, wearing only a towel, has even bigger breasts than he imagined. The girl, blushing at the sight, also frees her beautiful boobs for the prize money, aiming to clear the challenge.