Season 25, Episode 1: Treasures of Darkness - DCI John Barnaby and DS Jamie Winter investigate the drowning of mudlarker Johnny Hoxham in the River Midsomer, a death initially attributed to a sinkhole but quickly revealed as murder. The investigation uncovers a bitter rivalry between traditional mudlarkers and the more aggressive "Midsomer Magneteers," alongside the discovery of a 17th-century Wiccan jar believed to carry a curse. As the team delves deeper, another victim, Rufus Coulter, is found dead, and a connection emerges to the decades-old disappearance of Jesse Clissold, Alice Gideon's aunt, and a stolen 17th-century posie ring. Ultimately, Reverend William Gideon confesses to both murders, driven by a desperate attempt to conceal the truth about Jesse's past and the family's secrets. The episode concludes with Barnaby and Winter having successfully closed the case, leaving the village to grapple with the unearthed darkness.

Season 25, Episode 2: Lawn of the Dead - DCI John Barnaby and DS Jamie Winter are called to Midsomer Deverell's lawn bowling club after Wilf, the groundsman and referee, is found murdered following a tense competition. Their investigation uncovers a web of deadly rivalries, forbidden romances, and long-held village secrets among the club members. As Barnaby and Winter delve into the community's hidden lives, they work to unravel the complex motives behind Wilf's demise. The detectives are actively pursuing leads to identify the killer and bring resolution to the case.

Season 25, Episode 3: Death Strikes Three - At Godley Manor's engagement party, a booby-trapped cuckoo clock fatally strikes guest Brad Furbank, turning the celebration into chaos. DCI Barnaby and DS Winter arrive to investigate the unusual murder weapon, delving into a complex web of hidden pasts, family feuds, and ticking secrets within the village. The detectives work to uncover the truth behind the elaborate killing. The full resolution, including the killer's identity and final outcome, is not detailed in the provided search results.

Season 25, Episode 4: Top of the Class - DCI John Barnaby and DS Jamie Winter investigate the murder of strict headmistress Estelle Harris, who is brutally killed during a virtual PTA meeting at Causton Grammar School. The investigation delves into school scandals, rebellious teenagers, a disgruntled school secretary, and a mysterious local author. This case marks Midsomer's first-ever online murder, presenting a unique challenge for the detectives. The detailed resolution, including the killer's identity, motive, and the final scene, is not available in the provided information.