Biologist Margo Green (Penelope Ann Miller) teams up with police Lieutenant D'Agosta (Tom Sizemore) to investigate a series of grisly murders at her place of work - the Natural History museum. Can there be a link with the recently-arrived crates belonging to a missing anthropologist from Brazil? All that is found in the crates are some leaves covered with a strange fungus, which when analysed proves capable of mutating whoever eats it. When a guard is killed and a headless body interrupts the museum's exhibition gala, Margo and D'Agosta discover that there is an ancient killer monster on the loose.