It's local council election day at Dolphin Cove Public School. Dirty tactics turn deadly when one of Reggie's fellow candidates is poisoned by passion fruit sponge cake. But how did the killer get the poisoned slice to their victim?

With suspects and motives in surplus, this is a case for Dolphin Cove's incumbent, brilliant detective Mackenzie Clarke, but it will be a long day at the polls for her. Suffering from self-doubt and heartbreak, she has lost her crime-solving mojo. Can Glenn get Mack back in the game, or will their campaign to find the murderer stall?

A wildlife park worker is stabbed with their ornamental cassowary claw in a cassowary enclosure. The victim was the only one to access the cage, so how did the killer escape?

1983. A young surfer leaves Dolphin Cove in pursuit of his dreams. Forty-three years later, his remains are found in the concrete by the ocean pool. But how is that possible when he left town before the concrete was even poured?

Mackenzie has her work cut out, with decades separating the investigation from the crime. The grim discovery stirs painful memories of Philomena's past, forcing her to confront history and heartache. Glenn's no stranger to that as he struggles to let go of his feelings for Mack, all while her connection with his replacement Leo blooms.

Lights, camera, murder. The anniversary screening of Dolphin Cove cult horror film Blood Wave goes off with a literal bang when one of its key creatives is killed during the iconic gunshot sequence. But how did the killer fire the gun in front of the packed house without the audience realising?

Theories abound, and not just about the murder, as Colin questions what significance the film holds for Mack and Glenn. And as the case builds to its climax, Mackenzie doesn't know whether it's harder to solve the crime or give Leo an answer when he asks her out on a date.

Solitary Mackenzie Clarke reckons with the arrival of her uninhibited house guest. When a happy-go-lucky builder dies after falling from the roof of a construction site, she is immediately on the case. Mack knows a bodged-up job when she sees it. This was no accident, this was murder. The further Mack digs, the more she uncovers: a history of debt blackmail, illicit trysts and buried secrets.

How could anyone have pushed the victim when he was alone on the roof? And there's another mystery she has to solve - the secret Colin's keeping from her.

Resident wedding ruiner Mackenzie Clarke is paying the price for Glenn's absence. With Phil offside and a disastrous first impression made with new colleague Leo, she's not winning any popularity contests in Dolphin Cove.

So when an artist dies on stage in front of an audience during an avant-garde performance piece for the Dolphin Cove art fair, Mackenzie is dismayed to find that their main suspect, the victim's muse, has a surprising and complicated connection to her. Though Mack is well-versed in the art of mystery, even she can't figure out why the victim was clutching a red jelly baby.