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.

Every year, the Vibrant Villages competition fiercely pits various areas of Dublin against one another to see who has the most desirable community, leading to dirty tricks and sabotage. However, things go farther than expected when Harry's good friend Evelyn Summers finds the dead body of her estranged husband in her fish pond and tasks Harry and Fergus with discovering who killed him. 

A fellow P.I., Harry Benedict, inveigles his way into Harry's life by sending a particularly perplexing case her way. As Harry and Fergus attempt to work out how it's possible for a mystery writer to shoot himself in a locked panic room without a gun, they find the key to cracking the case might come from a very surprising source. 

When the director of a daytime Irish soap opera has his throat cut in the middle of a scene, Harry and Fergus are tasked to find the culprit as soon as possible so filming can resume. Fortunately, enough, Harry discovers a secret weapon in the shape of super fan, Orla. 

Harry and Fergus have to contend with a rival private detective, a gangster's henchman and an utterly baffling mystery when the girlfriend of a head chef's decapitated head is served up on a platter. Elsewhere, Paula makes a huge, life-changing announcement and Glenn pops the question to his long-time girlfriend, Petra. 

When Jamie D, the lead singer of Lola's favourite boy band, plummets to his death right before the band's farewell performance, Lola convinces Harry and Fergus to investigate.