One day, when college student Wataru comes home, he finds his older sister and three of her beautiful co-workers having a drinking party. The attractive older women take an interest in the innocent Wataru, and one by one they try to seduce him using their adult charms. The older women make him dress up as a woman and play with his dick, and he gets fucked in the cowgirl position next to his drunk older sister. This is a story full of exciting situations that every boy dreams of!