Roger St. Luc investigates a brutal murder suicide in a luxury apartment complex, uncovering a secret medical experiment gone wrong. The culprit, Dr. Emil Hobbes, created a parasite designed to act as a sexually transmitted aphrodisiac. The organism has already infected multiple residents, including Nicholas Tudor, who begins exhibiting violent physical symptoms. As the parasites multiply and spread through the building's closed environment, Roger and his partner Rollo Linsky realize the outbreak is turning the residents into hyper-sexual, violent carriers. The infection jumps from person to person in the hallways and common areas, overwhelming the isolated community.