Billy & Billie (2015)

Billy & Billie, a comedy from acclaimed screenwriter Neil LaBute (The Shape of Things, In the Company of Men), centers on two young adults (Adam Brody and Lisa Joyce) as they fall in love. They face the usual barrage of attention from their friends and family, and the normal anxieties that come at the start of a new relationship—all further complicated by the fact that they’re stepbrother and sister.