Waka and Daisuke, a couple newly in love, decide to enjoy a hiking trip together during the autumn foliage season. Building a pure and tender relationship, they share their first kiss on this special day, taking their bond to the next level. However, on their way back, they get lost deep in the mountains and eventually stumble upon a remote mountain lodge inhabited by monstrous men. Drawn to Waka's stunning beauty and voluptuous body, they brutally assault her in front of Daisuke, subjecting her to repeated creampie sex day and night. Before long, Waka's belly begins to swell with a child whose father could be any of them.