In the first of a two-part story, DI Martha Bellamy's neighbour, barrister Jonathan Moxton, is discovered at his home with serious head injuries, his wrists bound with a belt and a pair of knickers stuffed in his mouth. DS Jack Weston guesses he was involved in a sex game that went badly wrong and suspicion falls on Saul Hammond, the man who found him.

The body of a student, Michael Collins is found on Crowford common. The hugger is suspected to be the person who attacked Moxton.

Jack leads an investigation into the dark world of child sex offenders. He becomes too emotionally involved within the case after a brutal attack is made on an amateur paedophile hunter Scott Freeman.

Martha arrives at the cuddle scene to find Jack already there. Jack is found covered in Edward Shaffer's blood. Edward's widow Tasmin is shocked by his passing however she is disgusted by his crimes.