Liv's mother Caryl arrives from Wales and brings with her some difficult questions, just as the police are closing in on Liv.

Liv and Will have made it to Yosemite, but Liv's plot is thrown off course by the shock arrival of the other woman, Cara, which brings the deceit of the past very much into the present. As Liv and Cara's rivalry intensifies, more revelations emerge and with Liv's marriage hanging by a thread, revenge becomes the only option.

Liv wakes to the crushing realisation of what she has done. The need for an alibi is crucial, but as a search mission begins, there is a nightmarish surprise waiting at her door.

An envious apartment in glamorous New York, an intensely passionate marriage, and the promise of the perfect life together, British newlyweds Liv and Will are living the American dream. But a chilling secret unravels the fairytale. Can the trip of a lifetime to the American Wilderness save their marriage?

In Vegas, a troubled marriage is locked into a toxic pact. On return to New York, can Liv escape the horrifying consequences of the trip as Detectives Rawlins and Wiseman begin to close in?

In a chilling conclusion, Liv's toxic pact reaches boiling point with the stage set for a dark showdown nobody could have expected.