Belle Sterling loves to spy on her very sexy neighbors, Aden and Kevin, but she doesn't dare approach them to introduce herself. Until one night when they not only give her an erotic show, they hold a simple note against the window—"Come Over—#19." She does, and she has the night of her life. It soon becomes apparent to her that she's interested in a lot more than casual sex—but the two men have been in a relationship with each other for over a decade. Can they make room for her in their lives? That question becomes even more pressing when Kevin and Aden are forced to choose between professional advancement and Belle's best interests. They all must decide if what they share is merely searing sexual passion—or something far deeper.