A woman has her heart stabbed in a Dublin hotel. Mark Callaghan is at the top of Detective Byrne's list of suspects. Cait Roche agrees to help him find the murderer. The woman's husband is in Bulgaria but her brother, her business partner, is in Dublin, and inherits her shares after her death. Cait fights for her life when a burglar breaks into her apartment. Only the killer knows why she is next to be killed.