A time-traveling serial killer is impossible to trace--until one of his victims survives. In Depression-era Chicago, Harper Curtis finds a key to a house that opens on to other times. But it comes at a cost. He has to kill the shining girls: bright young women, burning with potential. He stalks them through their lives across different eras until, in 1989, one of his victims, Kirby Mazrachi, survives and starts hunting him back. Working with an ex-homicide reporter who is falling for her, Kirby has to unravel an impossible mystery.