Time to run. Time to hide. Time to die...

A late summer heatwave seems to have triggered an unusually high number of suicides. As the dead bodies pile up, DS Jack Mackinnon and the rest of MIT realise things aren't as straightforward as they seem, and when similar letters are found at the scene of each 'suicide,' Mackinnon is convinced they are dealing with a serial killer. A killer who is determined to deliver his own deadly justice.