Shelly Mohan, a housewife and mother of three, is forced into a desperate act when a man from her past tracks her down. Her husband, Jason, is a detective in the Garda, desperately keen to get an anticipated promotion.
Shelly’s husband, Jason, a Garda detective, is delighted to be assigned to the case, with no sense where the trail may lead. While he and his co-worker Fiona focus on a sex worker, Shelly realises she may have left evidence in the dead man’s hotel room.
As Shelly attempts to maintain her routine, she is haunted by her past. When Lynch's true identity is discovered, a UK cold case officer re-opens a case which she is convinced involves Lynch and his then girlfriend.
Shelly's attempts to bond with Derek are not a success. Meanwhile, following the lead of the hotel sex-worker, Jason and Fiona discover victims of a brutal trafficking organisation.
Jason reminds Shelly to attend the police station for fingerprinting and DNA testing. Glencara houskeeper Eileen gives a description of the woman seen leaving the dead man's room.
Niall's physiotherapist identifies Shelly as the woman at the hotel, and Fiona informs Jason that Shelly's DNA matches that found on the dead man's belongings. Meanwhile, the body of Mariama is found in the sea, seemingly having fallen or been pushed from the cliff.