Two farmers of Midsomer Worthy are at loggerheads over the proposed development of Setwale Wood. James Harrington of Abbey Farm wants his land felled, whereas his ex-friend Simon Bartlett of Grange Farm will do anything to stop this going ahead with the help of friend and barrister Bernadette Sullivan. However, all of this is pushed out of their minds when Simon's wife Susan is found dead in the Wood by some local children. Even though her parents don't believe her, Julie Fielding is adamant she saw the woman's body. When Mr Fielding sees the body, too, the next day, it is in the pond in Setwale Wood and it is confirmed that Mrs Bartlett committed suicide. After the trees start to be cut down, another body turns up, leaving Barnaby and Troy to believe that both victims were that of murder. With the help of little Julie and her brother, D.C.I. Barnaby learns of the Wood's history and a web of lies and secrets beneath the surface of this picturesque village. Julie Fielding tells her brother, Sean Fielding a story.. " The children walked through the woods for hours and hours. The trees got bigger and bigger and it was getting dark. There was lots of thunder and animals made horrid rustling noises in the night - foxes and wolves and a huge big bear." A Worm in the Bud" lulls in pacing in the middle with the-kids-playing-detectives not adding to the story as much as it could have done. Agreed also that the murders are on the bland side this time, in a show where they can be brutal and sometimes elaborate, and also on that it was an annoyance about not being given an explanation for why Susan wasn't killed straight after being made unconscious (if indicated in the episode, it was very vague to me).

Growing up in Midsomer Worthy, Victoria was the prettiest girl in the village, and forever won the heart of farm worker Jonah Bloxham. He maintained a shrine to her in a small rustic cottage in the woods, even after she had moved on and married into the Bartlett family. Following her husband's passing, her son Simon inherited the family farming business, passed down through the Bartlett bloodline for generations. James Harrington - drugged with Valerian and placed in a pit of mud, in which he asphyxiated to death.Julie spies the dog from the woods. Julie and Sean follow the dog. The barks and comes after them. Sean tosses him sausages. Jonah comes out and says no one comes here. he says, "I know who you are. You come again and I'll have you. You will know the winepress of the wrath of God." The people of Midsomer Worthy are attempting to keep James Harrington from razing Setwale Woods and turning it into housing. This apparently means that the farm owned by Simon Bartlett will be lost. He teams up with an attorney, Bernadette Sullivan, to stop Harrington. In fact, they team up in more ways than one.

Some of the residents of Midsomer Worthy are trying to prevent James Harrington from turning Setwale Woods into a housing estate. Led by a solicitor, Bernadette Sullivan, and a local farmer, Simon Bartlett, who also happen to be having an affair, they have not had much success in court. When Bartlett's wife, Susan, is found dead in the woods, Barnaby and Troy must first determine if her murder is related to the planned development or something as yet unknown. The information provided by two inquisitive children, who see the investigation as a fascinating game, proves invaluable in solving the crime. Simon goes over to Bernadette's. He says, "I went to Abbey Farm last night. I didn't know someone was going to kill James. He wasn't even there. I'm frightened, Bernadette. I went to the farm. I went home. I was on my own. He could have been there dead when I was." Bernadette says, "Did anyone see you at Abbey Farm? No. Then you weren't there. And you weren't on your own, you spent the night with me. An alibi from an eminent barrister should even shut Barnaby up." Julie digs around in her mother's garden. She watches Victoria Bartlett next door. Julie goes over to speak to Victoria. Her mom, Denise Fielding, watches her and talks to her husband, Sam Fielding. "She's doing it again. Victoria Bartlett, garden inspection. Every time she tells me how well it's doing she means 'must try harder'." She adds, "Julie's still sulking. She normally forgets these stories after five minutes. I've got to exercise the hounds so she can come with me. I'll go up where they were playing, have a look." Hannah Harrington walks through the gate to Victoria's house. She notices the cut flowers. In the side yard, blooms are arranged to look like a body. Still, it's a good episode with a good ending. The best scene is the children boarding a bus for Causton and going to see Barnaby at home. He isn't there, but Joyce is, and the little boy isn't interested in the mystery -- he just wants food.Most of the script is well written as "A worm in the bud" has a lot of colorful characters, compelling subplots and very tense solution that I didn't see coming. James is at a phone booth at night making a call. "Hi, how's it going? Shut up. I'll tell you when I see you. Don't keep me waiting. Any trouble and you know what's going to happen." Simon goes to James house at night and yells for him and blasts his horn. No answer from James. Setwale Woods are owned by James Harrington, who is determined to start a forestry clearance, despite vocal opposition. Most vocal in opposition is local farmer Simon Bartlett and lawyer Bernadette Sullivan, with whom Bartlett is having an affair. Harrington and Bartlett get into a fight outside the court house and injudicious words are said. Some time later Susan Bartlett is found dead in a pond in the woods. There are some untied endings at the end. For example, why was the first victim in the bushes six hours before she is found in the pond? That is never answered, though the murder mystery is built on this fact... Barnaby goes to Mrs Harrington's house. Victoria says the flowers will grow again. Barnaby wants to know if there Is anyone she would regard as being an enemy or someone her son would? Victoria says people often fall out with each other but she doesn't know anyone who would do such a thing.

One of the people that know about valerian locally is Jonah Bloxham. As Barnaby closes in on Bloxham, Bloxham is found in his blazing house. He is just about alive and taken to hospital. In his burnt out house Barnaby finds the remains of a photo of a child. Later he finds the remains of a similar photo on the bonfire of Victoria Bartlett, Simon Bartlett’s mother. Victoria Bartlett is not at here home, but the children have seen her being taken away at gun point by Hannah Harrington, James Harrington’s mother. At Jonah's house, someone comes in and hits him over the head with a wrench. He falls to the floor. All the photos are removed and the place is set on fire. A drunken James runs out of the pub in the rain. He drives past Victoria Bartlett and splashes her. He almost hits another car. At court, the judge says, "I understand the feelings of the Midsomer Worthy community. Setwale Wood has been a place of recreation for generations. Children play there, people walk their dogs, picnic, and I'm sure all sorts of things. But none of that alters the fact that the land belongs to Mr Harrington. As for this long list of objections, nothing warrants an injunction to prevent Mr Harrington selling his wood, or Whitley Estates felling it." The audience sighs.Simon and Bernadette have words. Simon doesn't care about a court case against Harrington anymore. Bernadette says Simon will get Abbey Farm when this is all over. Ever since they've met Simon banged on about what you could do with more land. Bernadette says she can make that happen. Simon says, "Can't you wait till she's buried?" Bernadette retorts, "What is the period for abstaining from carnal knowledge of your mistress when your wife dies? If she'd walked out you'd have thrown a party. It's the same woman." Barnaby explains to Troy, "Susan Bartlett had to be replaced by any woman who could provide a grandchild. But Harrington worked it out. He put the flowers in Victoria's garden. Not to say, "You're next." Just, "I know you did it." Troy says, "But why would Bloxham frame Simon Bartlett?" Barnaby says, "He found out what she'd done, but he wasn't part of it. Yes, she learned all about valerian from him some 40 years before. But Bloxham was trying to incriminate Simon because Simon was about to break his mother's heart by selling the farm. The farm was everything to Bloxham. He grew up there. And Victoria, she was five years younger than him, but she was like a kid sister. Hannah said she idolised him. And he loved her. But they couldn't stay kids forever. So he turned the only time he was happy into a private world. He had to protect it. Even Simon was expendable. Victoria didn't see it like that." When two children report a body in Setwale Woods, no one believes them until their father sees it, now in a different place. The body is that of Simon's wife, Catherine, an unhappy woman who left a suicide note. It's later determined to be murder. Then there's another murder. So who's doing the killing, and why? In this episode, Barnaby gets some crucial help from the brother and sister, whose parents are tearing their hair out with worry. There is a big hole in this script, which is that no one ever says why the Bartlett farm will be lost if the housing development goes up. Harrington could not have forced Bartlett to sell his farm, yet there seems to be a great deal of angst about holding onto it.