An old sanatorium. A terrifying murder. Six suspects and a case that never closed . . . Discover the new locked-room mystery by the Sunday Times bestselling author Once a hospital dedicated to treating tuberculosis, The Akureyri Sanatorium now sits haunted by the ghosts of its past. But a single wing remains open, housing six employees. When one of the hospital's nurses, Yrsa, is found brutally murdered, it sets in motion a series of terrifying events. Despite just six suspects, the case remains unsolved two decades later. Until young criminologist, Helgi Reykdal, attempts to put the mysteries of the hospital’s past to rest . . .