Simona Sana is a young pathologist whom 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 theses about natural deaths when one "suicide" victim is brought into the morgue in which a young Catholic priest named Paul Lenox who identifies the corpse as being his sister, but that she did not commit suicide, and was instead murdered then subsequently set up to make it look like another suicide. 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.