I've been dating my girlfriend for half a year. Her name is Hiroshi. Her mother, Yuki, is a beautiful, hardworking single mother who raised her daughter alone—a mature, composed woman. I get along very well with my girlfriend and see her almost every day. But behind her back, a special relationship has developed between me and Yuki. When we're alone, we can't suppress our desires; our bodies react instinctively, grinding hips together in uncontrollable passion. Both Yuki and I know this affair is wrong, yet neither of us can bring ourselves to stop. This film portrays the complex emotions arising from our secret relationship.