Glasgow 2024 - Clem waits by her daughter's hospital bed. Erin was found on an idyllic beach in Fynhallow Bay, Orkney, with catastrophic burns and only one memory: her name is Nyx. But how did she get these burns? and how did her boyfriend end up burned alive? Orkney 1594 - Accused of witchcraft, Alison Balfour awaits trial. The punishment? To be burned alive. Seperated by four hundred years but bound by the Book of Witching, two women stand imperilled. Can they unlick a centuries-old mystery? And will Fynhallow Bay give up its secrets before someone else dies?