Six Silent Killings: Ireland's Vanishing Triangle

Lisa's article criticizing the Gardaí for not acting on Amy's disappearance is leaked; David and Det. Brennan chase a lead in Castlemoy; impatient with the police's pace, Lisa risks her life to uncover what that lead is hiding.

David tries to get a statement from Teresa and a confession from Bulger; Lisa investigates Bulger; Susan pleas for information on an anonymous informer from the Gardaí.

Lisa has to choose whom to save between Susan and Mandy; Chris learns new information that takes Lisa to a strange address, where she discovers incriminating information.

David and Brennan target Gough as the potential killer; Lisa tries to connect him to the kidnappings; Gill threatens to blackmail David if he continues his investigation of Gough; Lisa receives a call about her father from the hospital.

The investigation is halted; David confronts Gardaí's top officials to expose Gill and Gough, but he finds no support; Lisa and Brennan follow a lead on the killer, investigating an abandoned slaughterhouse.