Detective Colette Cunningham takes a call from Dublin, where she has been named next of kin to her murdered daughter Kate, who vanished 20 years prior.

After a visit from organised crime, Collette is more suspicious than ever about Stacey's supposed suicide and pieces together clues that point to a culprit.

Colette follows up on a case that leads her into contact with someone who knew Stacey, which results in a new lead - Stacey's last call.

With a suspect in her sights, Colette closes in on the truth; with Patrick and Siobhán's help, Colette finally discovers corroborating evidence.