The Butterfly Effect 3: Revelations

A man with the ability to leap back and forth though time attempts to help a childhood friend solve her sister's murder, in the process breaking his own golden rule and creating an evil that didn't exist previously. Sam uses his gift to help solve the crimes that leave detectives cold. Though it pains him to know that he can never intervene directly during his leaps, he knows that the consequences could be terrible if he does. Approached by his old friend Elizabeth to help track down her sister's murderer, Sam obliges. But this time things are different, and Sam's inner demons force him to break the one rule that he has always upheld. Upon returning from his leap, Sam discovers that his slip up has given birth to a maniacal serial killer that would never have existed otherwise. Now, as the death toll continues to rise, it's up to Sam to dive back into the past and uncover the killer's identity before any more lives are lost.