An elderly man living with dementia turns up on the police station steps, clutching only a photograph of Humphrey. He's searching for his sister, Louise, and believes that Humphrey is his last hope. But with precious few clues to her whereabouts, the team must work against the clock to unravel the mysteries of his past.

Just as they dive into the search, the station is rocked by another call. There's been a break-in at a local wine bar, where the team celebrated their Christmas party just hours before. On top of this, Kelby is called to an unusual emergency: a man hopelessly trapped inside a snowman suit after his head was glued on as a prank. As the clock ticks down, could the snowman hold a vital clue to solving another festive mystery?

With an influx of unexpected visitors, a slew of holiday crimes to crack and a heartwarming reunion on the line, can the team juggle it all and still be ready for a life-changing reveal?

When nurse Lucy vanishes on her way to the hospital, all eyes turn to Kelby's long-standing nemesis - Josh Woods. Is he up to his old tricks again? But after Josh receives a chilling voicemail, the team start to suspect that something far more sinister is at play. In the recording, Lucy can be heard shouting 'Devil!', followed by a beastly growl. Josh reveals that Lucy's route to work crosses the Devil's Hump, a mound on the outskirts of town rumoured to claim the souls of those harbouring dark thoughts. Could the local legend hold a vital clue to unlocking the mystery of her disappearance?

After accidentally crossing the Devil's Hump, Kelby grapples with his own fears surrounding the superstition. While Esther remains a steadfast sceptic, Kelby starts to see signs of the 'devil' everywhere. Opening his mind to the unexpected leads him to an unlikely friendship with Josh. Can they finally put aside their differences to find Lucy?

As the case intensifies, Humphrey finds himself torn between the personal and professional. With Rosie's birthday fast approaching, he and Martha are determined to throw her the perfect party. But as they start to enjoy family life, they start to forget how easily things could change. Will their world be torn apart? Elsewhere, Esther faces the consequences of her impulsive decision making. Noticing a shift in her mum's mood, Zoe decides to take matters into her own hands.

As the harvest ends, Stella and George Ellis follow their long-held tradition of hanging a corn doll to mark its close. But this simple ritual takes a darker turn when the doll mysteriously falls and a figure dressed as the mythical Cornman strikes. With their milk ruined and their hay set ablaze, the Ellises are pushed to the brink. Can Humphrey unmask the saboteur before their livelihood is completely destroyed?

Meanwhile, Martha and Humphrey embark on a new chapter as foster parents when Rosie begins her first day at Shipton Abbott Primary, while Anne takes a bold step to embrace life to the full.

It's the final day of the regatta, and rival sailors Francine and Polly are neck-and-neck for the top spot. But just as the race gets under way, disaster strikes. Polly collapses and plunges into the sea, throwing the entire race into chaos.

When it's discovered that Polly's smoothie had been tampered with, suspicion starts to grow. All eyes turn to Martha, the seemingly innocent smoothie maker, who now finds herself in the spotlight as an unlikely prime suspect. Martha and Humphrey, already juggling the demands of work and childcare, struggle to stay composed under this new pressure.

A local chocolatier falls under suspicion when three customers are poisoned after sampling her confections. Humphrey must explore every avenue to determine whether she orchestrated the attack or was framed.

The mystery deepens as the team finds no trace of poison in the remaining chocolates – how did the perpetrator ensure the victims ate the right one? With public panic spreading across Shipton Abbott, the team must work swiftly to uncover the culprit.

When Kelby's old friend Emily becomes the target of threatening texts, the team must act fast to uncover who's hiding behind the screen. With Humphrey busy at home, Kelby steps up to help Esther with the investigation, facing endless potential suspects as they delve into the world of social media and online spats.

Meanwhile, Humphrey and Martha have a rocky start as they welcome Rosie – their new foster child – into their home and grapple with how to best care for her.

Elsewhere, new relations are formed as Esther finds herself in a surprising romantic entanglement and Anne finds solace in an unlikely friend when rocked by a potential health scare.

When a body is found in the river on the county border between Devon and Cornwall, Humphrey and Esther are thrown in at the deep end, having to work alongside their Cornish counterparts. While their rivals are quick to brush off the death as a tragic accident, Humphrey's instincts tell him there may be more lurking under the surface.

Meanwhile, Martha has her hands full as Ten Mile Kitchen expands to a bigger and bolder venue. With the demands of their careers ever-growing, Martha and Humphrey start to consider what their future may hold.