Lovestruck Callum is jealous of Leila's handsome 'friend'. Finn has more serious concerns, convinced the visitor is here to do Leila serious harm - and she's gone missing.
Former Judge Ginette Prince sent a lot of dangerous people to prison in her time so, when someone sets fire to her home, the police officers wonder if the motive is revenge.
Niamh and Shay are partying on the beach when a hooded figure rugby-tackles a lad to the ground. The figure reveals himself as Niamh and Shay's dad, Inspector Finn O'Hare; he saw the lad trying to sell drugs to the kids.
When an ATM machine is stolen, new detective Al crosses a line to save someone he loves. Meanwhile, Finn struggles to cope - and has a difficult conversation with Siobhan.
Feathers are ruffled when Port Devine's champion pigeons are stolen. And, as Finn falls to pieces, a frustrated Siobhan turns her attentions elsewhere.
An investigation into a drug-spiking pushes Finn over the edge - and he ends up injuring one of his own officers. Meanwhile Callum discovers Siobhan and Al's secret.
A fishing trip ends in disaster when the boat's engine blows up - who's to blame? Callum sees Al breaking the law - and tells Finn that Al is a corrupt cop.