Four hundred years separate them. One book binds them. 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. Separated by four hundred years but bound by the Book of Witching, two women stand imperilled. Can they unlock a centuries-old mystery? And will Fynhallow Bay give up its secrets before someone else dies?