A lucky guy gets invited by Nao Jinguji to stay the night at her place. After a party, the guy misses the last train home, and one of her coworkers, Nao Jinguji, invites him to stay at her place. He doesn't think much of it at first, especially since he already has a girlfriend. But the sexual innuendo and teasing start to escalate and he eventually gives in to the temptation. And then the two of them make love from night to morning and whether this relationship will continue or not,.