On 9 February 1983, Detective Chief Inspector Peter Jay is called to the leafy North London address of 23 Cranley Gardens, where he discovers the drains clogged with rotting flesh and bones. When the culprit, Dennis Nilsen, returns from work, he freely admits that it’s not just one or two bodies but “15 or 16, I think”. As the police try to secure a conviction and identify the victims, biographer Brian Masters begins a game of chess with `Des’ in an attempt to understand his motives