© ITV/Mark Bourdillon

Eric Calder, the boss of Calder's Biscuits based in Badger's Drift, collapses and dies on a business trip to Copenhagen as he opens a tin of his company's famous Golden Clusters, coated with deadly strychnine. The toxic package was posted from Midsomer so Danish detective Birgitte Poulsen asks Barnaby to investigate.


Barnaby and Nelson find Eric was on the verge of pulling off a major deal to supply Toft biscuits in Copenhagen. His son Harry has no desire to go into the family business - he's more interested in Summer Haleston who works in Mrs Trout's Tea Room.


At Calder's factory, Barnaby meets the man behind Golden Clusters - baking genius and flamboyant eccentric Armand Stone, who with Eric's assistant Clara Trout is putting the final touches to the Copenhagen order. Tempers flare when Barnaby discovers the killer tin was sent from Calder's and shuts down the factory. Meanwhile, Harry comes home to find his mum Penelope in bed with his uncle, Eric's brother Julian.


Stone has a degree in chemistry and a barely hidden ambition to take over the company - but he denies synthesising strychnine in the laboratory and instead points the finger at Harry, who rowed with his dad the day before he died.


At the funeral, Barnaby spots a floral tribute with a message in Danish - meaning 'forever' - while antique dealers Atticus and Ernest Bradley are desperate to get their hands on Eric's valuables. Then Penelope names Julian as Eric's successor.


Danish police find a fingerprint on Eric's hotel door. Julian gets a phone call and goes to the factory but is struck on the head. The next day, Clara discovers a strange scene - a chair tied with ropes, surrounded by empty bottles of spirits. And Julian has disappeared.


Harry admits phoning Julian but claims he was drunk and only wanted to confront him about his relationship with his mum. He also says Eric had told him that he was leaving Penelope.


Julian's body turns up at Toft's, strapped to a pallet. He was drowned in whiskey. Barnaby and Nelson fly to Copenhagen where Poulsen reveals Eric's floral tribute was bought using a credit card stolen from local pastor Thomas Madsen.


Albert Toft says Eric was planning to sell him his business but the detectives discover he had more than biscuits linking him to Copenhagen - he had also bought a cabin in the name of Ingrid Madsen. Thomas initially denies knowing Eric, but his prints match the one at the hotel. What's more, Poulsen finds that Ingrid had a baby girl 20 years ago who was given up for adoption. Although Eric never knew, he and Ingrid had recently rekindled their affair.


Barnaby and Nelson work out the identity of Ingrid and Eric's daughter and rush back to Midsomer as another two bodies are found. Who knew the truth about Eric's double life and what is the real secret of Calder's Golden Clusters?