Rinka, who is unaware that she is a new half, is asked by two friends to be a practice partner for a kissing session when they consult her about sex. Reluctantly agreeing, Rinka finds the situation escalating when her friends reach for her crotch, only to discover something hard there. It's then that they realize Rinka is a new half, much to their surprise, but excitement takes over, leading to them having sex.