Yuma is sexless with his wife and visits a delivery-health shop to relieve it. Waiting for him is Rena, his mother’s friend. He panics and tries to leave; she smiles as a pro and says the fee is already paid and invites him in. From that day he is captured by the forbidden pleasure of the mom-friend and, knowing it is not allowed, goes back to the shop again. The affair deepens from the no-sex shop into home meetings.