Shelly Mohan, a housewife and mother of three, makes an irreparable decision-and commits a horrific act-when Charlie Lynch, a man from her troubled past, contacts her.

After realizing that she may have left evidence in Charlie's hotel room, Shelly concocts a scheme to destroy it at the police station.

As a teenager 20 years earlier, Shelly was part of a drug ring in London with Charlie Lynch, the man she shot. When Lynch's true identity is uncovered, a UK officer, DSI Crichett, reopens an old murder case linked to Shelly and Charlie.

The investigation builds steam in both countries as Jason's partner, Fiona, grows suspicious of Shelly. The reasons why Shelly changed her identity emerge.

Shelly tries to change her fingerprints, while the investigation in London develops new leads despite political pressure to close the case. New witnesses give descriptions of the suspect that may point to Shelly.

The pressure builds on all fronts as Shelly is identified as the mysterious woman at the crime scene and Jason tries to close the case. Shelly considers fleeing, but she would never leave her children behind.