Rivalry Turns to Friendship in 'All Creatures Great & Small's "Uninvited Guests"

Tristan Farnon relates a hair-raising wartime encounter as All Creatures Great & Small reaches the season's halfway point. James and Helen listen enthralled to his story, which builds to a tense climax when he recounts how he felt a pistol at his back. But the notorious prankster has fooled them – it was, Tristan says, a camel digging its nose into his spine as a reminder that breakfast was required. As they stroll through Darrowby with the pram and baby James, Audrey Hall meets them with the news that farmer Sid Crabtree (Ryan Hawley) called about his cow. Since Siegfried has gone to pick up Richard Carmody from the train station, James is on call.

We met the Crabtrees in Season 4, a couple new to farming who almost lost their herd and livelihood in a brucellosis outbreak, and James is pleased to hear that things are going much better for them now. Sid has a new dog, Shep, whose primary interest in life is to creep up on people and surprise them by barking loudly. But Sid is worried about his cow Rose, who won’t eat. James recommends linseed oil.

Tristan may be telling fun stories, but he's not too pleased to learn he now shares a bedroom and is even more alarmed when he meets his roommate. (Richard had been taking his veterinary exams in London, almost certainly acing them.) Tristan invites him to the pub, but he declines since he has some bacteria from London for his evening entertainment. He and Siegfried plan a cozy evening with microscopes and Latin quips. Appalled, Tristan mutters his brother Siegfried multiplied, spawning a mini killjoy. Who in their right mind would choose bacteria over booze? Richard asks Tristan about the war and receives a dismissive answer. Finding no one wants to go to the pub, Tristan goes alone and returns drunk later that night to the closet, which is his share of the bedroom. No wonder he is beginning to feel that he is the stranger here and that Richard has taken on the favorite role.

Audrey tells Siegfried she’ll make Tristan more comfortable by finding a second-hand mattress for the closet. Over breakfast, Tristan and Richard grab the last slice of toast, ripping it in two. Siegfried receives a call from Mrs. Pumphrey, whose house has been requisitioned to become a hospital. A snake, smuggled in by one of the patients, has escaped. Audrey volunteers to help Tristan and Richard catch it, believing that working together will improve their relationship. 

When they arrive, Mrs. Pumphrey is having issues with Matron Herbert (Caroline Chesworth). Although initially pleased to offer her house, Mrs. Pumphrey is upset by her move, worrying that a favorite painting disappeared. The overworked, understaffed matron is polite but firm – she cannot help. Tristan insists the snake is imaginary and doesn’t want to look for it. Richard wanders into the house and meets wounded soldier Harry Tucker (Bailey Brook), reading Dickens with Tricki Woo (Dora, new this season) on his lap. Richard asks him about his service abroad, and he replies that he loved the heat, the food, and the sights, but for him, the best part was coming home. 

Tristan interrupts just as Richard asks Harry about his wound, and Tricki Woo creates a diversion by running off again. Tristan and Richard give chase and corner the dog in a small room. Tristan scolds Richard for his intrusive question about Harry’s injury as they discover they are locked in. Oh, and the room's population has increased with the presence of a not-so-mythical python. Richard realizes Tristan is terrified; he apologizes for taking over the room. It means a lot to Richard after a childhood spent in boarding schools, and it’s his first opportunity to put down roots. Just then, Mrs. Pumphrey comes to the rescue, and Richard assures her they’ll take the snake to Skeldale House, where their room will provide a perfect habitat. (Poor Tristan.)

James is perplexed that Rose’s condition hasn’t improved and annoyed when the postman, Mr. Oakley (Nicholas Collett), weighs in. His recommendation? “A right good gallop,” James tells Crabtree that he became sick with brucellosis and left the RAF, the first person to know outside Skeldale House. Having failed so far with science, Mr. Oakley gives the cow a gallop. Helen visits James and is there as he listens to the cow’s abdomen with his stethoscope. The cow is miraculously cured! Whether it was a question of time or the gallop, James doesn’t know, but Helen suggests they go to the pub to celebrate. They are interrupted by Shep doing what he does best, exploding out of his hiding place with a flurry of deafening barks. James, taken by surprise, shouts at Shep, who runs off.

Having told Crabtree about his experience with brucellosis, James now tells Helen his crew was shot down when he was sick. He won’t or can’t talk about it anymore – he’s made his peace with it. There’s a happy resolution to the mystery of Mrs. Pumphrey's missing picture. Matron finds it by chance, and the two women make their peace. The image, painted by Mrs. Pumphrey’s father, is of the house where she lived as a child.

James, feeling bad for yelling at Shep, returns with a bone for him. He’s delighted to see Shep stalk, attack, and bark at Mr. Oakley, who flails and falls in a shower of letters. Tristan’s sleeping arrangements are much improved with his new mattress but he really doesn’t want to share the room with a snake. Audrey isn’t very happy with the thought of a snake in the house, and Siegfried, while admiring the creature, fears his pet rat Volonel might be in danger. Richard admits that after talking to Harry he’s wondering if he should sign up for military service, but Tristan advises against it. Tristan and Richard are becoming friends and can now admit they enjoyed their escapade, and they’re both happy with the decision that the snake will be donated to a zoo. Richard pays Tristan the highest compliment: “You’ve grown on me. Like bacteria.”

All Creatures Great & Small Season 5 will stream/air weekly through mid-February (check your local listings) on most PBS stations, the PBS app, and the PBS Masterpiece Prime Video Channel. All seven episodes of Season 5 are available now on PBS Passport, and Seasons 1-4 are streaming for members. Season 6 is already greenlit and expected out in 2026.