After losing his parents, Shinjiro moved in with his older brother and his wife. His sister-in-law, Aki, was left unfulfilled in her intimate life with her husband, Kotaro. The two of them are drawn into a forbidden relationship by a sudden turn of events. One night, Aki discovers Shinjiro asleep in his room, half-naked and holding a porn magazine. The sight awakens her suppressed desires. His rock-hard erect cock ignites a fire deep within her heart. In that instant, everything between them changes.