Simona Sana is a young pathologist who works in a morgue in Rome, Italy which suddenly gets hit with a wave of violent suicides that are attributed to a summer heat wave. Driven to exhaustion from the intense heat and the long hours worked, Simona struggles to complete her college thesis about natural deaths- when one "suicide" victim is brought into the morgue identified by a young Catholic priest named Paul Lenox as being his sister. He claims she did not commit suicide but was murdered. Simona teams up with Father Lenox to solve the mystery and stay one step ahead of a mysterious killer who now begins to stalk her when she gets a little too close to the truth of the suicides.