In the tradition of Italian horror from the 1960s, Sibling Rivalry is a dark tale of secrets, lies and masked killers run amok, while still retaining a sense of humor. Camille, 15, and her sister Ariana, 12, return to their secluded summer home on the isle of Victoria, where a year earlier, their mother committed suicide. Their father, James Stockman, producer of a popular TV series Memoirs of a Teenage Necromancer, insists that the trip is good therapy for them all. Shortly after arriving, Stockman is called back to Los Angles on ‘business’ leaving the girls home alone. In defiance, the girls throw a party with some local teens. That’s when the fun begins. As the body count rises, multiple masked killers surface, and terrifying family secrets are revealed.