When the lead officer of a joint investigation is hospitalised, evidence retrieved supports the unbelievable reports that have been coming in.

DI Dan Higgin is sent to take over the operation in NW13. He's to solve and conclude this gruesome case that had been thought closed.

Dan's used to dealing with strange cases and interference, but the nature of the assailants and the escalating number of victims forces some unusual choices upon him.

As he and his team start to discover what's behind the situation, more mysteries come to light. The motives of those causing the mayhem are tangled. Some are modern, others rooted deep in the past.

What eventually becomes clear is the nature of the threat.

In a race against time, they must unravel this mix of mad science, elder secrets, greed and revenge before it kills them all and goes on to kill thousands more.