Mai, a childhood friend of two brothers who share a room together, arrives. The older brother and younger brother have always liked Mai, and the three suddenly start living together. Now adults, their relationship doesn't stay the same as it was when they were children. The older brother crosses the line, and the younger brother, seeing this, also ends up having a relationship with Mai. To settle the long-standing love triangle, Mai suggests a threesome with the brothers. At first, it's awkward, but the group play gradually becomes more enjoyable, and the relationship between the three deepens...