Percy wins a competition and heads off for a day out at Gadget Heaven Theme Park - but not before he's instructed Gordon in the finer point of his garden maintenance schedule. Unfortunately, the Chief Gnome has other plans for Percy's garden and insists that Gordon supervise the trainee Ian Gnome in looking after the garden to further his education. Predictably, Ian's talent doesn't live up to Percy's rigorous standards and Gordon has to solve numerous gardening disasters. Can Gordon get the garden back into perfect condition before Percy returns that evening?

Gordon loses his magic hat! A gnome’s hat is as precious as a fairy’s wand, and without it, strange things start to happen to remind Gordon to keep looking for it. After one day his nose turns into a pinecone. Then his hair grows long and green. Then his boots grow three times larger!! Everyone, except Gordon, finds this very funny! Can Gordon find his hat before things get really out of hand?

When an unusual plant arrives unexpectedly in Gordon’s garden, Gordon assumes there’s been a mix-up in the Gnome Post. But Percy, Rosie and Jerome aren’t expecting a delivery either, so Gordon sets off with Andrew around the world, to return the plant to its proper home. In each location Gordon discovers clues as to the plant’s natural habitat - whether it likes hot or cold, dry or wet climates – and they soon find the owner. But the Chief Gnome is hot on Gordon’s heels looking for the plant too - it’s a surprise present for his wife Gladioli’s birthday.

Lez and Dez, the Slugs, want to get their own back on Gordon for never letting them eat the gardens’ plants. When Gordon’s not looking they sneak under his hat and repeat a magic growth spell they have just overheard Gordon use. Lez and Dez are soon ordering Gordon to give them food and because they are bigger than him, he can’t refuse. But when Gordon finds out how the Slugs became large he tricks them into believing that they have eaten all the food in the world. Then he puts them on a strict diet and exercise regime to get them back to their normal ‘small’ selves again.

The Sparrow Sisters, want to take a bath but their birdbath is empty and the fountain isn’t working. Gordon replaces the broken water pump with a brand new super-pump from Percy's Gnome shopping catalogue. Unfortunately, it’s so powerful it empties the entire pond! So, Gordon creates an ingenious water system that gets water from the tap at the far end of his garden to the pond, creating a fantastic water theme-park ride at the same time. Everyone has great fun at the new lido.

Horace and Doris, two posh Snails, arrive in Gordon’s garden looking for a second home. Lez and Dez take a disliking to them and send them off into Percy’s garden, where they hope they will fall foul of one of Percy’s bug-catching contraptions. But Gordon offers a more ‘friendly’ solution to their housing problem, and builds them a top of the range Double Bin Compost Heap. Lez and Dez are furious and decide to ‘raid’ their house warming party.

Gordon helps a little lost lamb called Fluffy find his mother – but this cute little lamb isn’t quite as sweet and innocent as he makes out. He’s actually very naughty. While Gordon and Rosie are out searching for his Mummy, Gordon’s garden is in danger of being eaten!

Gladiloli loses her diamond engagement ring in the ocean, when holidaying at the seaside with the Chief Gnome. So, the Chief Gnome calls Gordon away from his garden to dive in and recover it. Gordon and Andrew discover the most amazing underwater garden in the ocean, but find it very hard to get Gladioli’s ring back. It’s in the possession of a couple of angry sea slugs, called Ron and Don, who don’t like underwater tourists and have some very unusual ransom requests!

When a ‘self-digging spade’ goes out of control, Gordon uncovers a treasure chest buried deep in his garden. Unfortunately, the thought of great riches divides the Gnomes and animals, who each want the treasure for themselves. Even the Chief Gnome gets a bit greedy and claims the treasure is his! But Gordon isn’t interested being rich. He has all the riches he needs, living in a beautiful garden and being able to share it with his friends. But he could do with a new toolbox….

Gordon, Percy and Jerome Gnome are invited to Ian’s school as guest teachers to give gardening lessons. Percy’s lesson is on tidiness and how to create a scare-bug. Jerome demonstrates how to ‘let the grass grow under your feet’ and the art of making ‘To don’t lists’. But it is Gordon’s ‘Let’s get Mucky’ gardening approach that proves a big hit with the kids.

Gordon orders an Apple Tree for Rosie’s birthday, but with only a day to go until Rosie’s party, it still hasn’t arrived in the post. When it does arrive Gordon is surprised to find it is just a seed in an apple core. How can he grow a tree from seed in a day? Perhaps a little Gnome hat magic might help?

Gordon goes in search of Big Boot, the legendary Gnome that roams the woods behind his garden. Percy guides the expedition with the help of a "Nose on a stick" but ends up getting them all lost. And Gordon’s attempts to get a picture of Big Boot are thwarted by the Chief Gnome and Gladioli, who keep frightening him off. Rosie manages to lead them all home with her natural tracking ways – where it seems that Jerome has spent all afternoon in the company of Big Boot!

It’s Gordon’s turn to host the Gnome “Sprummer” festival and the Chief Gnome asks him to put on a play. Everyone is to take part and the theme is ‘The Four Seasons’. Gordon is Spring, Rosie is Summer, Jerome is Autumn and Percy is Winter. Andrew heads up the orchestra and Lez and Dez introduce the acts. Unfortunately, things don’t go quite as smoothly as Gordon has planned.

Percy installs an intruder alarm in his garden and warns Gordon "strange things can happen at night". When a mysterious noise keeps Gordon awake that night, Gordon is a little bit spooked, so he decides to investigate. At the same time, Lez and Dez are planning a secret night raid on Gordon’s vegetable patch and it turns into a very busy night in the garden indeed.

Ian is left with Gordon for the day to take his mind off wanting a pet. When Ian works hard in the garden, Gordon rewards him by making him a model dog from vegetables. It’s a Veggie-pet. Ian calls him Radish. At first Ian thinks Radish is pretty cool, but he still wants a real pet. So Ian brings Radish to life with a little bit of Gnome hat magic and Gordon has to teach him to be a responsible pet owner.

Gordon learns to play his hat like a trumpet for the Big Frog Hop, which is to be held in his garden for the first time. Percy, Rosie and Jerome all join in and Gordon soon has a Gnome hat band quartet for the big event. The Chief Gnome wants to join in too, only can’t find an instrument that suits him. Gordon manages to solve the problem by making the Chief Gnome the conductor.

Gordon and friends accidentally activate the Chief Gnome’s new ‘Weather Predictor’ machine and can’t turn it off. When Andrew asks it to tell them what the weather was like millions of years ago, a T-Rex jumps out of the time portal, leaving them with a very big dinosaur problem. How can they get the dinosaur back to its own time zone without the Chief Gnome finding out?

A series of mishaps in the garden put Gordon in a bad mood. His trike’s front wheel gets stuck in one of Morris’ molehills. The loose plank on Jerome’s fence squashes his hat and Percy’s ‘cloud generator’ drops a rainstorm on his garden by mistake. Taking a break, Gordon discovers his old diary and reads about his first meeting with each of his friends. He re-discovers what is special about all of his friends and his mood brightens.

Jerome discovers a well in his garden and asks Gordon to take a look at it. Believing it might be a "wishing well" Gordon makes a wish and encourages all his friends to do the same. But there’s something not quite right about the well. It’s keeps asking for lettuce leaves to be dropped inside before it will grant any wishes. Gordon is suspicious that Lez and Dez, the slugs, might have something to do with it!