Yesterday, upon the stair, I met a man who wasn’t there....

In the afterglow, the grid vanished, and Ryan’s breath caught in her throat when she saw what remained. There was Jean, walking through her living room just as she had imagined her. Except, this woman was outlined in a halo of blue light—a hologram with every living detail that had been Jean—when she was alive.

When gifted homicide detective Ryan Mills is recruited to a top-secret FBI division known as S.P.E.C.T.E.R., the world of the supernatural becomes more real than she could have ever imagined. She is introduced to an incredible device known as LAZARUS, which can replay the events of a crime with the smallest pieces of available evidence. With the help of her new partner, Special Agent Sam Masters, and Dr. Matthew Holbrook, the research scientist who created Lazarus, Ryan is plunged into the paranormal exploration of unsolved murders.

But Ryan holds a secret, one she can’t share with her partner or Holbrook. That secret comes back to haunt her when a homicide crime scene holds clues to someone from her past and has torn at the edges of an eighteen-year old cold case: the disappearance and possible murder of her own sister. The killer has scrawled a message meant only for Special Agent Ryan Mills:

"Yesterday, upon the stair, I met a man who wasn’t there...."

He's back. The only person who knows what happened to her sister. And he knows something about Ryan too...something even she doesn’t know—yet.