On a beautiful spring day in a city park, a woman watches her child on a swing. A dark figure in a trench coat stares at them from a distance. He watches as the woman is suddenly attacked and brutally murdered. 

He watches, but does nothing.

He is SAM REED, a private investigator who uses his ability to leap back in time to solve the city’s most vicious crimes. The information he gathers from his time travel to the past brings criminals to justice in the present. The one rule Sam lives by is that he must not alter the past because such a change could create a horrific new reality in the present.

The next day, Sam is visited by a young woman, ELIZABETH, a girl who Sam remembers from their teenage years. Her sister, a classmate of Sam’s, was murdered ten years ago, and Elizabeth asks Sam to find her killer.

Sam goes back in time to the scene of the murder and discovers that not only has Elizabeth’s sister been murdered, but also Elizabeth!

It soon becomes evident their murders were the first in a string of killings. Sam realizes that his inquiry into the past has created a serial killer.