Detective Jemima Huxley is called out to a gruesome scene in an isolated rural valley town.In Rhymney Valley, an area long-since left behind after the closure of the mines, two men have been bound and hanged from a strange old iron structure.From the decomposition, it's clear the bodies have been here some time. Birds have pecked the men's faces to ribbons. They both have something carved onto their foreheads - but in their current state, it's impossible to work out what.Jemima sets up a task force in the nearest station, but there are soon rising tensions between local police and these big-city detectives. The old guard have never encountered a woman in charge before. For Jemima's team, it's like stepping back in time.Then Jemima hears about a spate of unexplained deaths among young people in the area. Could it be connected to these grisly murders?Whatever is going on out in these valleys is darker than anything Detective Jemima Huxley has ever seen. It will take everything she's got to crack this case - before any more young lives are lost.