The newest thriller from #1 Bestselling Author Sarah Pekkanen combines a decades-old mystery with spine-tingling paranormal elements in this twisty novel of the seen and unseen. When 80-year-old Betty Sadler hires Riley Bell, a down-on-her-luck divorcee, as a live-in aide, it seems like a lifeline - even if Betty's house is a strange time capsule from the 1960s. Betty has one final wish: she wants Riley to find her three best friends from college. But when Riley begins to investigate, she discovers the first woman murdered her husband, then took her own life, the day Betty abruptly left the college. The second friend was institutionalised for schizophrenia hours later. And the third disappeared forever. Riley soon learns Betty and her friends were part of classified university experiments and that Betty is haunted by what transpired inside the Institute’s Room 6. But whatever was swirling around these four exceptional young women is rising from its long-dormant state. Someone is trying to resurrect the old experiments, like a copy-cat serial killer. And Riley's efforts to get answers about the lost girls of the Room 6 is putting her on a collision course with the person who wants to finish the job.