
After Montreal police officer Mia Coleman and her partner Tyler take a lenient approach to a marital dispute, the husband, Paul Whitman, murders his wife Keri and their two small children, then kills himself. But Mia has stumbled across Plan B and finds herself able to book a trip into the past, and perhaps alter the outcome.

Police officer Mia Coleman is haunted by a case involving a murder-suicide. She calls the Plan B agency, determined to go back in time and prevent the tragedy.

Traveling back in time to prevent a murder-suicide, Mia kidnaps the would-be killer, but her plan backfires, leaving blood on her own hands in her pursuit of justice.

Suspended from duty, Mia's determination to prevent a sexual assault leads her down a path of vigilante justice, blurring the lines between her police work and her personal vendetta.

Mia travels farther back in time to protect Keri from her abusive husband, forcing Mia into proximity with her own ex-boyfriend Bryson and confronting her with the complexities of their relationship.