Harry Wild S03E06 - Dead Man's Trigger

In the season three finale, Harry and Fergus head to the Garda station to collect Charlie, Orla and Lola en route to Glenn and Petra's wedding. While there, a despondent man takes the station hostage and demands that they help solve the murder of his daughter. Concerned, because Harry has the ring, Glenn comes to check on them and realises he has a Die Hard situation on his hands.