The Vanishing Triangle

After investigative journalist Lisa Wallace publishes an article about her mother's murder, girls start to disappear; she and Det. David Burkely investigate across Ireland, searching for the missing girls, while the killer taunts Lisa.

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.