Troubled solicitor Nick Turner falls to his death from the roof of his apartment in Sandford House, Midsomer Magna, in front of his wife Felicity and neighbour Antonia Wilmot. Is it suicide disguised as murder so Felicity can still claim a hefty life insurance payout?

Rival solicitor and Roman expert Otto Benham was spreading rumours that Nick was stealing his clients' money but Nick's partner Jeff Martin denies it.

DCI Tom Barnaby and DS Dan Scott go to quiz night at the pub but Jack Wilmot doesn't show up to join his teammates, Otto and former TV quiz show host Mike Spicer.

Nick's former employee Jane Hampton thinks Nick was involved in a shady business deal with the disgraced Peter Blagdon, while Antonia has a nightmare Jack is locked in a secret wine cellar under Sandford House.

Otto claims he's never met Blagdon and suggests Jane was in love with Nick. But after the police leave, Otto phones a worried Spicer and tells him to keep quiet. Scott finds a picture of Peter Blagdon but Jane insists he is not the same man Nick met. Then Jeff Martin discovers £150,000 is missing from his client account funds.

Otto is eating dinner with his long-suffering and disabled wife Bernie when an intruder in a black balaclava drugs his wine and trusses him to the lawn like a human target using croquet hoops. He is then fired on with bottles of vintage wine from his replica Roman catapult. Bernie is restrained in an upstairs room but cannot resist enjoying her husband's demise.

The next morning, Barnaby and Scott find faked wine labels in Otto's safe. It appears he was involved in an elaborate forgery scam. Then Antonia discovers a trap door in an outbuilding. But as the detectives investigate the now empty cellar they are locked in. Can they crack the case from a locked and airless room - and can they get out in time to stop another murder?