A detective desperate for revenge. A hitwoman with one last job. A killer with both on his list. Detective Matt Jackson's beloved wife, Polly, is the latest victim of a serial killer - Neon - who displays his victims amongst snaking neon lights. Suicidal but unable to kill himself, he hires someone to finish the job. But on the night of his planned murder he makes a breakthrough in the Neon case and offers his assassin, Iris, an irresistible opportunity: help Jackson find and kill Neon in return for his entire estate. What follows is a thrilling game of cat-and-mouse between detective, assassin and serial killer. But when Jackson discovers it's not a coincidence that their paths have crossed, he begins to question who the real target has been all along...