A young woman, Fiona Holland, has gone missing from a small Irish village. A search is mounted, but there are whispers. Fiona had a wild reputation. Was she abducted, or has she run away? A week later, a gruesome discovery is made in the woods at Ireland's most scenic beauty spot - the valley of Glendalough. The bodies are all young women who disappeared in recent years. D.I. Tom Reynolds and his team are faced with the toughest case of their careers...

Christmas day, and DCI Tom Reynolds receives an alarming call. A mass grave has been discovered on Oileán na Caillte, the island which housed the controversial psychiatric institution St. Christina's. The hospital has been closed for decades and onsite graves were tragically common. Reynolds thinks his adversarial boss is handing him a cold case to sideline him. But then it transpires another body has been discovered amongst the dead - one of the...