After Ami and her stepbrother Hiroshi share a night together, the phone rings with devastating news: their parents have died. A year later, Ami lives with Hiroshi and his wife, Mariko. On the surface, the couple appears happy, but tension simmers between Ami and Mariko. One day, Mariko lashes out at Ami for constantly intruding into their bedroom uninvited. Losing her composure, Ami blurts out her the secret of her history with Hiroshi.