In 1981, the Alpha Gamma Theta sorority is hosting a party, welcoming new pledges. However, an unexpected visitor also makes an appearance. Unbeknownst to the sisters, someone is lurking in the darkness, observing their every move. As the girls go about their daily routines—showering, studying, eating, and sleeping—the stalker meticulously watches them. He targets each girl when they are most defenseless, taking their lives one by one. The police are on the case, searching for the missing girls and their murderer, but will they arrive in time? Or will the sorority sisters have to fight to survive?