As the curtain draws on the final episode of "All Creatures," Mrs. Pumphrey (Patricia Hodge), accompanied by her beloved Tricki, steps into Skeldale House for a meticulous examination with the ever-diligent James Herriot (Nicholas Ralph). With a hint of concern, she reveals that Tricki has exhibited an unusual couch-like behavior, yet curiously, the pup remains cough-free in James' presence. James, ever observant, notes the excess sugar in Tricki's diet and requests an update should the cough resurface.
Elsewhere, Audrey Hall (Anna Madeley) engages in a chat with Helen (Rachel Shenton) about procuring sugar for jam-making, intended as a gesture of kindness to send to Pumphrey Manor. Siegfried Farnon (Samuel West) re-enters the scene, recounting an encounter with Arkwright's temperamental sow before mentioning his need for a jacket clean-up. He then learns of a message awaiting him from Mr. Dobson and attempts to reach Miss Grantley.
Helen discovers James taking a well-deserved nap upstairs, his fatigue evident after a lengthy session with patients. Siegfried learns that Tristan Farnon (Callum Woodhouse) has been engrossed in grading course papers and tasks him with additional duties now that the academic responsibilities have concluded. Tristan, however, cites upcoming students as an excuse, though Siegfried's mention of a missing book, suspected to be the goat lady's Persian memoirs, piques Tristan's interest further. He reveals he has Grantley's draft, albeit slightly marred by an accidental spill.
Helen informs Audrey of her success in procuring additional sugar and offers her assistance. Siegfried inquiries about James' handling of tomorrow's appointments, reminding him of his lack of an assistant. Tristan suggests Siegfried visit Miss Grantley to discuss the book, but Siegfried replies she is away. Reluctantly, Tristan agrees to lend a hand tomorrow, albeit warily of Siegfried's constant oversight.
Arriving at Molly Stephens' (Olivia Paige Marsh) farm, Tristan and Siegfried greet her and inspect Barley, the horse Molly intends to use for pony rides. Molly expresses her concern about Barley's behavior around children. Helen checks on James, who now seems much more cheerful. However, an argument ensues between Tristan and Siegfried over Barley's treatment, with Siegfried eventually taking charge, administering a precise dosage with an air of precision. He realizes more is needed but is reluctant to follow Tristan's suggested increase.
Audrey, overwhelmed with work at Skeldale House, takes a call from Mrs. Pumphrey, who voices her anxieties about Tricki. Audrey notices James' peculiar demeanor. Siegfried's attempt to adequately treat Barley falls short, prompting Tristan to step in successfully. James, now ready to see Tricki, is greeted by Pumphrey's concern about the dog's facial pawing. James reassures her that Tricki is in peak health. Pumphrey, concerned for James' well-being, asks after him. Helen arrives just as James begins to show signs of overheating. Mrs. Pumphrey alerts Helen to James' delirium, and together with Audrey, they gently escort him to bed.
Pumphrey instructed them to immerse him in cold water to alleviate his fever. She readily agreed to take charge of the ailing infant. Meanwhile, Tristan and Siegfried finally caught up with Mr. Dobson (Jon Furlong), who proudly presented them with Algernon. Dobson requested Siegfried's expertise to examine the new acquisition, while sharing tales of Tristan's wanderlust adventures and hinting at a potential gift for him. As Dobson stepped away to retrieve the item, Tristan lent Siegfried a helping hand. Helen, concerned, informed James that his symptoms might indicate another brucellosis flare-up, deciding to call a doctor if his fever surpassed 100 degrees.
Downstairs, Pumphrey and Audrey concurred that something was troubling Tricki. Audrey suggested waiting for Siegfried's assessment, but Helen's interruption revealed the doctor's opinion that such fevers were common with brucellosis, emphasizing the need to keep James cool and comfortable. Audrey volunteered to stay with Jimmy downstairs, allowing Helen to focus on James. Pumphrey offered to keep watch over James herself, noting Audrey's preoccupation.
Dobson, eager to please, wanted to gift Tristan two bottles of his renowned elderflower wine. Siegfried pronounced Algernon in excellent health, with his teeth in perfect condition, until Tristan called out, noticing something overlooked – a suspicious patch that resembled sweet itch. Siegfried had the necessary injection but warned of a fee.
Back at Skeldale House, Helen diligently attended to James, while Tristan was tasked with administering the injection to Algernon. However, the horse unexpectedly collapsed upon Tristan's attempt, though Siegfried swiftly reassured Dobson that all was well as Algernon regained its footing. Audrey struggled to manage her duties at Skeldale House, prompting Pumphrey to take charge of answering incoming calls.
Stranded in their car, Tristan and Siegfried pondered Algernon's sudden collapse and争吵over who was responsible for refueling. James murmured incoherently, mentioning Banerjee, then broke down in sobs, lamenting his perceived failures. Helen comforted him, assuring him everything would be alright.
Walking to safety, Tristan and Siegfried delved into war stories, with Tristan arguing that Siegfried underestimated his war experiences. He urged Siegfried to ask Miss Grantley out as a gesture of camaraderie. Pumphrey jotted down details of the Skeldale House calls, while Audrey worriedly contacted Dobson's farm, inquiring about their delay. Encountering water, Tristan attempted to carry Siegfried across on his back.
Audrey and Pumphrey exchanged worries about Tristan and Siegfried's whereabouts. Helen informed them that James had awakened, requesting tea and toast, and she became emotional while holding Jimmy. Siegfried expressed his hope for deeper conversations with Tristan post-war, feeling they should connect on a more intimate level. Tristan countered that they had never been talkative, to which Siegfried questioned why they couldn't change. He gently prodded Tristan to occasionally spend an evening at home for camaraderie's sake.
Later on, James offered Helen an apology, should he have caused her any concern. Helen, in turn, mentioned his conversation with Banerjee, prompting James to recount his recent ordeal. He was consumed by guilt, believing that his illness had let everyone down. Meanwhile, Pumphrey cradled Jimmy as Audrey diligently worked on preparing the jam, contemplating whether they ought to taste it first to ensure it wouldn't harm anyone.
Elsewhere, Siegfried confessed to Tristan that he had intended to invite Grantley over for dinner. He had offered her some constructive feedback on her book, but she hadn't taken it well. Their discussion had been lively, to say the least, and they hadn't spoken since. Siegfried had continued reading her memoir and found it vastly different from the tranquil Darrowby. Tristan joked that he and Siegfried had a similar effect on the opposite sex, believing that older ladies found Siegfried irresistible.
Eventually, they made their way back to town. James apologized to Pumphrey for his earlier behavior, to which she gently reminded him that he had been delirious. Suddenly, Tricki started scratching again, prompting James to take a closer look. He discovered a tiny chicken bone lodged between Tricki's teeth. Just then, Siegfried and Tristan created a commotion outside, drawing everyone's attention.
