Detective Matt Jackson has reached the end. His beloved wife, Polly, is the latest victim of 'NEON' - a serial killer who displays his victims in snaking neon lights - and he can't go on without her. Unable to take his life, Jackson hires a hitwoman to finish the job. But on the night of his own murder, he makes a breakthrough in the case, and at the last minute his hitwoman, Iris, is offered an irresistible alternative: help Jackson find and kill NEON in return for the detective's entire estate.