THREE DAYS BEFOREMara Vale wakes at 3:17 a.m. with blood on her hands, blood on her clothes, and no memory of how it got there.Her best friend, Elena Hart, has been murdered.The evidence begins to point toward Mara almost immediately. Her blood-stained clothes. Her missing coat. Her car abandoned near the crime scene. And a piece of black fabric found clenched in Elena’s broken fingers.Then the police discover something that makes the case impossible to explain.Security footage shows Mara standing over Elena at exactly 1:43 a.m.—covered in blood and staring directly into the camera.The problem?Mara was asleep in her bedroom at 1:43.As Detective Daniel Cole digs deeper, Mara's missing memories become increasingly disturbing. Strange messages appear on her phone. Someone seems to know exactly what she remembers—and what she doesn't. Then a single note is discovered:SHE WASN'T THE FIRST.Mara begins investigating her own past, only to uncover fragments of a history she doesn't remember living. People who know her seem to know things she has forgotten. Old records don't quite match. And somewhere in the darkness, someone is determined to make sure she remembers.With three days remaining before a date she cannot explain, Mara must uncover the truth about Elena's murder—and about herself—before the next body is found.Because the most terrifying question isn't who killed Elena?It's—How many times has Mara done this before?