Angela Throgmorton is leading a somewhat lonely life when a strange, scruffy, creature appears on her doorstep. Feeling sorry for the poor thing, she takes it in, feeds it and cleans it up. However, when the creature manages to flood the house, Angela decides to find another home for it. This soon teaches Angela two lessons: firstly, that no-one wants the creature; and, secondly, that she really quite likes him. However, Old Tom and Angela get separated, and Angela goes home alone. Then a storm hits. Angela, learning that the creature has taken shelter in a storm drain, goes off to rescue him. Surfing through the drain on her ironing board, Angela snatches her new friend just before the storm-waters can wash him away. Angela takes him home and calls him Old Tom.

Told by her friend, Lavinia, that she and Old Tom should 'smarten themselves up', Angela takes Old Tom to the local department store to buy new outfits. There, they bump into Lavinia, who insists on taking them shopping. Lavinia leaves Old Tom to play on a children's ride, as she takes Angela around the store, buying increasingly silly outfits for her. Meanwhile, Old Tom breaks free from the ride and causes mayhem around the store, much to the anger of the store manager, Mr Pangborn. Angela, in her new outfit, gets away from Lavinia, just as Old Tom, in disguise, manages to escape Mr Pangborn. They both end up in the Missing Persons department, where they recognise each other and, shedding their silly outfits, decide they don't need to smarten up, after all.

Old Tom is getting in Angela's way as she tries to tidy the house, so she suggests he goes outside and find a friend. However, outside Old Tom is teased by Billy and, worse, trapped by a savage dog. He is saved at the last moment by a young girl called Lucy. They hit it off immediately, and Lucy invites Old Tom around to her place to play. Unfortunately, they are followed by the savage dog, who bursts into Lucy's house and causes mayhem. Old Tom and Lucy lock the dog in her room and escape, just as her parents come home. They think Old Tom caused all the mess and forbid Lucy from seeing him again - that is, until they accidentally let the dog out. Then Old Tom and Lucy, using one of Angela's vacuum cleaners, manage to get rid of the dog, and teach Billy a lesson.

Angela goes shopping for a playhouse for Old Tom and ends up buying an old rocket ship. Old Tom loves it and, with his best friend Lucy, they decide to fly it to Mars. Angela thinks they are just playing (after all, the booster rockets have been taken off) and she goes along with their little 'fantasy'. However, while she is cleaning the rocket, it takes off - Old Tom had used one of Angela's vacuum cleaners as the propulsion. The rocket flies off into space with Old Tom on the inside, and Angela on the outside, battling meteors and satellites. Finally, Old Tom lets her in, just as the rocket careens out of control and crash lands on an unknown planet. Angela is sure they're on Mars - but one of the aliens looks familiar. It's Lavinia, and they have literally 'crashed' her garden party.

Lavinia decides to 'elevate the cultural tone' of Angela's household, by giving them regular musical recitals on her violin. Her talent, however, is negligible, and Old Tom and Lucy can't stand the racket. When Lavinia and Angela go out for a cup of tea, Old Tom has a go on the violin and discovers he is a prodigy, fiddling a tune so fast that he breaks all the strings. Lavinia returns, but doesn't notice the broken strings because she is in a hurry to get to a TV talent show, on which she is a contestant. Lucy and Old Tom hope Lavinia wins because the first prize is a trip around the world - which means no violin recitals for six months! However, they realise she can't win, because her violin has no strings. So Old Tom, grabbing another violin, races off to give Lavinia a helping hand.

Lavinia takes Angela with her to the beauty salon for a complete makeover . Angela is reluctant, but agrees to go if Old Tom can come, too. At the salon, they are greeted by the temperamental owner, Istvan, who mistakes Old Tom for a particularly hairy customer and tries to give him a beauty treatment. In Old Tom's struggle to escape, Istvan ends up bald instead, and chases Old Tom furiously around the salon. Old Tom hides in Lavinia's room, where he is mistaken for a beautician, and told by Lavinia to begin her 'full treatment' immediately. Old Tom gleefully obliges, using whatever odds and ends he can find. Istvan bursts in just as Old Tom is finishing. Lavinia looks bizarre, but she likes her new look and thanks Istvan, who can only smile and take the credit.

Angela tries to get her old car repaired, but is talked into trading it in for a new car, instead. The salesman persuades Angela and Old Tom to test drive a sports car, but Angela drives so timidly that Old Tom floors the accelerator. The car zooms through town, attracting the attention of a traffic policeman who gives Angela a ticket. Angela returns the sports car and next tries a four-wheel-drive. But that is too powerful, so she tries a limousine which is so sophisticated she can't even drive it. Eventually, Angela decides to keep her old car, but learns it has been taken to the wrecker's yard. So Old Tom has to race off and save it.

Angela falls off the roof while trying to retrieve Old Tom's golf balls, and is confined to bed. She suggests getting Lavinia to look after the house for them, but Old Tom - fearing how Lavinia might treat him - offers to run the house, instead. In his own way, Old Tom manages quite well. He tidies the house, cooks dinner, looks after Angela and even does the shopping - which is where Lavinia spots him. Suspicious that Old Tom would be allowed to shop on his own, Lavinia goes to Angela's house and finds her bed-ridden. Adopting the air of a martyr, Lavinia insists on running the house, and makes Old Tom's life a misery by making him do all the actual work. So Old Tom fakes an injury and ends up in bed with Angela, while Lavinia has to wait on them, hand and foot.

Lavinia comes to take Angela golfing. Old Tom and Lucy want to go golfing, too, but Lavinia tells them the golf club won't let 'undesirables' play - they have to stay home. At the golf course, Angela is excited because, even though she has never played golf before, she turns out to be a natural, and easily out-plays Lavinia. This infuriates Lavinia, who starts to cheat. Meanwhile, Old Tom and Lucy, sneak onto the golf course and spy on Angela and Lavinia - noticing that Lavinia is cheating. They secretly undo Lavinia's cheating, so that Angela wins the game. The club manager is so impressed with Angela's skill that he offers her life membership. But when he tries to chase off Lucy and Old Tom for being 'undesirables', Angela refuses, saying she'd rather be with her friends.

Lavinia takes Angela and Old Tom to the town's finest restaurant. Old Tom is horrified when the owner, Chef Geoff, serves them tiny portions, so he hijacks the dessert trolley. Old Tom gets thrown out, but he doesn't mind because he thinks his culinary nightmare is now over. Unfortunately, Angela has bought the Chef's cookbook and attempts to make his dishes at home. Even Angela thinks the food is inedible and returns to the restaurant to find out why the recipes don't work. By mistake, Old Tom's toy - a fishbone - gets put in the garbage. But when Old Tom goes through the bins to find it, he discovers Chef Geoff's guilty secret - he is really serving pre-packaged and out of date food. The restaurant is closed down and Old Tom goes back to his old diet.

Lavinia has entered Angela's house in a 'Tidy Home' competition, so Angela goes out to buy flowers while Old Tom tidies up his room. Angela specifically reminds him that ""not a thing must be left on the floor."" Unfortunately, Old Tom takes this literally and, with the help of Lucy, he takes everything off the floor in the house and throws it into the back garden, where they attempt to hide it by wrapping it all in curtains. When Angela returns home with her flowers she is shocked to see the place barren, and faints. Then the judges arrive. But far from being shocked, they are impressed by the bare floors and, especially, the big 'sculpture in the back garden. Angela's house wins first prize.

Old Tom is being pestered by a bird which has built its nest on top of Angela's chimney. The bird disturbs Old Tom's sleep, takes his food and fills the house with smoke. Old Tom is just about to squirt it off with a hose, when a bulldozer arrives. The driver explains he has come to knock down Angela's house, to make way for a freeway. He says Angela and Old Tom will be re-housed in a modern apartment block. They check out the apartment - but it's hideous, and they decide to stay in their home. As the driver starts his bulldozer, Angela, Lucy and Old Tom hold a tea party in front of it, blocking its way. Just then, the bird flies down to take Old Tom's food, and the driver recognises it as a rare species. Because it's nesting on the house, he can't knock it down after all.

Lavinia has entered Angela's house in a 'Tidy Home' competition, so Angela goes out to buy flowers while Old Tom tidies up his room. Angela specifically reminds him that ""not a thing must be left on the floor."" Unfortunately, Old Tom takes this literally and, with the help of Lucy, he takes everything off the floor in the house and throws it into the back garden, where they attempt to hide it by wrapping it all in curtains. When Angela returns home with her flowers she is shocked to see the place barren, and faints. Then the judges arrive. But far from being shocked, they are impressed by the bare floors and, especially, the big 'sculpture in the back garden. Angela's house wins first prize.

It's Angela's birthday and Lavinia has several treats planned for her. But she is annoyed that Old Tom is coming, too - especially when he gets them thrown out of a café. At Lavinia's next treat for Angela - a trip to the skating rink - Old Tom goes wild in a zamboni and covers Lavinia in ice. Furious, she refuses to let Old Tom go to the next treat - he has to stay with Lucy, instead. When Lucy decides to play dress-ups, Old Tom realises their costumes are so good they can follow Angela and Lavinia in disguise. They see Lavinia and Angela try to get into Lavinia's final treat for Angela - the -studded opening of a new Cineplex. However, the doorman rejects them for not being stars. So, Old Tom, posing as a celebrity, manages to get Angela and Lavinia into the opening.

Old Tom is upset when Lucy has to go to a friend's party, so Angela takes him to the beach to cheer him up. As Angela dozes, Old Tom gets up to mischief. He grabs hold of the tail of a kite, which carries him out over the sea and drops him onto what looks like a pirate ship. However, it turns out to be a pirate-themed children's party, and Old Tom eats all the food. When the kids discover what he has done, they tie him up and threaten him with 'Scarface, the meanest pirate of them all'. However 'Scarface' is really Lucy, and Old Tom is untied. Before the party can resume, the birthday boy's father, who has fallen overboard, is chased by a shark, so Old Tom grabs a rope and rescues him.

Lavinia persuades Angela to buy Old Tom a computer, so he won't get up to mischief. When the computer arrives, Old Tom is more interested in playing with the box, so Angela tries the computer instead. She is hooked immediately, surfing the internet and paying no attention to Old Tom or anything else. He takes advantage of this by getting up to mischief - preparing his own food, and kicking a football inside the house. But the fun soon palls for Old Tom - the place is a mess, he runs out of food, and he misses Angela. In desperation, he enlists the help of Lavinia and Lucy, who realise Angela is hypnotised by the computer. They rush her to the nearest café and give her a cup of tea. Soon, Angela is herself again - until she discovers it's an internet café!

Lavinia thinks her nephew, Billy, is a brilliant artist and hangs one of his paintings in Angela's living room. When Lucy and Old Tom see it, they think Angela must be desperate for a painting, so Old Tom paints a self-portrait to replace it. By mistake, it ends up at the Art Gallery in an exhibition of 'Modern Masterpieces'. Meanwhile, Lavinia is trying to interest the Gallery in one of Billy's paintings. However, the curator thinks it's rubbish and points to Old Tom's painting as an example of great art. Lavinia leaves, just as Old Tom and Lucy sneak in and retrieve his painting. When Lavinia arrives at Angela's, she is surprised to see the 'great example of modern art' hanging on her wall.

When Lavinia discovers that 'the great example of modern art' was painted by Old Tom, she takes it to a local gallery owner who offers to exhibit and sell Old Tom's paintings, and give Lavinia half the money. Lavinia greedily asks Old Tom to paint four more paintings, but he will only do so if she does something for him in return. Lavinia, desperate, agrees. As she runs around after Old Tom - buying him gifts, giving him treats, etc - Angela feels left out. On the day of the exhibition, Old Tom happens to be passing the gallery and, seeing all the food, bursts in and makes a pig of himself. When the art patrons realise this is the painter, they think it's a joke and don't buy his paintings. Old Tom doesn't mind. He takes the paintings home for Angela, and Lavinia doesn't get a penny.

Lucy is having trouble with her school project on Leonardo Da Vinci, so Angela takes her and Old Tom to the local museum to get more information. While there, Old Tom and Lucy play around on a replica of a Da Vinci flying machine, and actually make it work! They fly it around the museum to where a professor is explaining why Da Vinci's flying machines can never work. The museum curator is horrified that Old Tom and Lucy are playing in one of his exhibits, but the professor is amazed and delighted that they have made it fly. To Angela's delight, he congratulates the youngsters and helps Lucy finish her project.

Lavinia takes Angela, Lucy and Billy on a picnic in the countryside. When they open the picnic hamper, they discover that Old Tom has hidden inside and eaten all the food. Lavinia is horrified, but Lucy suggests they can fish for food in a nearby river. As they look for the river, they are chased by a bull, disturb a beehive and upset a farmer. However, when Old Tom manages to catch some fish by scaring them out of the river, all is forgiven, and the farmer is invited to join their picnic lunch.

With all his friends away for the holidays, Old Tom is bored - so Angela reluctantly sends him off to summer camp. Despite Angela's fears, Old Tom settles in immediately and makes new friends among the campers. Angela, however, is still concerned that Old Tom won't be able to cope without her, so she goes back to the camp and makes his bed, tidies his tent and brings him a bag full of supplies. The other campers make fun of Old Tom and when they go on their bush walk, they make him bring up the rear. However, when the campers get into trouble by falling into a raging, crocodile-infested river, Old Tom saves the day with Angela's bag full of supplies.

While Angela is sleeping, a couple of thieves sneak into her house and steal her most treasured possession - a valuable antique vacuum cleaner. Old Tom, however, sees them and hides in the back of their getaway truck, leaving a trail of sweetie wrappers behind him. When the thieves unload the stolen goods into their warehouse, they unknowingly unload Old Tom, too. Meanwhile, Angela wakes up and discovers that her vacuum cleaner - and Old Tom - are missing. With a policeman's help, she follows the trail to the warehouse, where Old Tom catches the thieves and hands them over to the policeman.

Old Tom overhears Lucy and Angela complaining about Billy, and mistakenly thinks they are talking about him. Devastated that not even his best friends really like him, Old Tom runs away from home and joins a circus. There, he is immediately accepted and told that he is not the 'no-hoper' he thinks he is. With the encouragement of the Ringmaster, Old Tom learns that everybody has a talent, and his talent is to make people laugh. Meanwhile, Lucy and Angela search the town for Old Tom and eventually find him in the circus - just as he is doing his act. They clear up the misunderstanding with Old Tom, telling him they were always proud of him and always will be, and he returns home with renewed faith in himself.

While playing frisbee, Old Tom accidentally breaks Angela's favourite record by her favourite singer, Tom Moans. Old Tom and Lucy try and buy a replacement copy, but it's impossible to find. When they learn Tom Moans is performing in town, they try and buy Angela tickets to the show, but it is sold out. Instead, they go backstage and try to get Tom Moans's autograph, but find him in tears - he has lost his chest hair wig, and won't perform without it. Old Tom has an idea. Lucy rushes off and brings Angela and Lavinia to the show. Angela wonders how Lucy got free tickets, so Lucy points to Tom Moans's orange chest hair. Angela looks through her binoculars - the chest hair is really Old Tom!

Old Tom wants some money to buy a toy, so Angela suggests he work for it - as a gardener. She lends him her old lawn-mower, and he soon has a job mowing the next door neighbour's lawn. However, mowing is hard work, so Old Tom attaches Lucy's remote-controlled toy to the machine and turns it into a remote-controlled lawn-mower. This is much easier, until he accidentally switches controls with Billy - then the mower zooms off out of control, with Old Tom holding on. The mower and Old Tom zoom around town, cutting a zigzag maze through the town park - but the Mayor, far from being angry, is delighted with the new feature and pays Old Tom for his work. Old Tom rushes off to the shops, but instead of buying the toy he wanted, buys a new mower for Angela.

Angela has to go to hospital for a small operation on her big toe, so she leaves Old Tom with Lavinia for the afternoon. However, Old Tom is very smelly (he had been hiding in a rubbish bin to avoid going to Lavinia's), and Lavinia makes him play outside. When Lady Winifred calls and invites Lavinia and Old Tom to her garden party, Lavinia realises that she has to wash Old Tom. But this is not as easy it seems, and Old Tom manages to foil Lavinia every time. But on the drive to the garden party, Lavinia has one final attempt at washing Old Tom - by driving through a car wash with the windows open. When they arrive at the party, Old Tom is finally clean… but Lavinia is a mess!

Old Tom hurts his tooth on a lollipop, so Angela rushes him off to the dentist for a check-up. The dentist has trouble coping with Old Tom - who plays with all the dental equipment - but finally says Old Tom's tooth will be fine, if he just gives up the sweet food. When Angela throws out all his sweets and buys healthy food instead, Old Tom starts to go delirious and imagines sweet foods everywhere. Thinking a street lamp is a giant candy cane, Old Tom bites it and hurts his tooth again. Angela rushes Old Tom back to the dentist but learns that the dentist was so exhausted by Old Tom's visit, he has had to take the day off. Angela finds the dentist at the beach where, with the help of some sun-screen, a beach ball, and an ice-cream stand, they manage to fix Old Tom's tooth.

A rather ordinary magician, called Morton the Affordable, is entertaining Billy's birthday party - not very successfully - until Old Tom's antics disrupt the party, and Morton's assistant quits. Morton desperately needs a new assistant for his appearance on an important TV show, and he picks Old Tom. This makes Billy jealous and, just before the show, he locks Old Tom in one of the magician's boxes and takes his place as Morton's assistant. The performance starts badly, until Old Tom escapes from the box and turns the magic act into comic mayhem. The audience is so amused that Morton becomes a big success and discovers the art of showmanship from Old Tom.

Old Tom has a nightmare about monsters, so Angela takes him and Lucy to an amusement park to cheer him up. Lucy wants to go on the Ghost Train, but Old Tom is too scared, and they play on the other amusements instead. When Old Tom accidentally breaks one of the games, he is chased by the park manager, and has to hide in the Ghost Train. At first Old Tom is frightened, but then he realises the ghosts and monsters are fake, and he has nothing to fear after all. Meanwhile, a young couple taking the ride think it is really boring, until they see Old Tom and believe he is one of the monsters. They congratulate the park manager, who thanks Old Tom and gives him a lifetime pass to the park.

When Old Tom is finishing his bath, his favourite bath toy - a rubber duckie - goes down the plug hole and gets stuck in the house's plumbing. Old Tom tries to retrieve the toy, but ends up soaking Lavinia, who has come for tea. On Lavinia's advice, Angela calls a plumber who, with Old Tom's help, tries to fix the problem. But he, too, accidentally soaks Lavinia. Tired of all the drenching, Lavinia leaves, only to be soaked again when the blocked garden hose explodes, flooding the house - but finally releasing the little rubber duckie.

Angela won't let Old Tom keep his new pet - a goat. However, instead of taking it back to where he got it from, Old Tom hides the goat in his room. Meanwhile, to make up for the pet, Angela buys Old Tom an insect-eating plant. To his dismay, the plant won't eat insects but, when his back is turned, it eats the food off his plate and grows bigger. When the plant tries to eat Angela, Old Tom rescues her in the nick of time and they flee the house. Meanwhile, Lavinia arrives, not knowing about the carnivorous plant. Angela and Old Tom return just as the plant is devouring Lavinia, and they manage to rescue her. At that moment, Old Tom's goat escapes from its hiding place and eats the plant.

Lavinia is organising a dance competition and wants Angela to take part. Angela, who loves dancing, is keen, but she doesn't have a partner. When Old Tom volunteers, Lavinia is horrified and tries to find an alternative. However, each candidate is secretly sabotaged by Old Tom, so Lavinia has no choice but to let him be Angela's dance partner. At the dance contest, Angela and Old Tom aren't doing very well, until Billy - who has a grudge against Old Tom - unleashes his super-flea on Old Tom. The flea makes Old Tom jump and leap about, which the judges interpret as brilliant and original dancing, and they award Angela and Old Tom first prize.

Angela has organised a cruise on the harbour for herself, Old Tom and Lavinia. However, when Lavinia discovers the boat is an old rustbucket, she refuses to join them, but goes for a cruise on a sleek new yacht instead. On the old boat, Angela and Old Tom aren't having much fun, when suddenly Old Tom catches, with his fishing line, a giant sea monster which pulls him overboard. Angela is terrified, but Old Tom is having the time of his life as the creatures pulls him along, water-skiing, and then gently puts him back on deck. It turns out the sea creature is very friendly so, thanks to Old Tom, the old boat's captain starts up a new enterprise - sea monster rides!

Angela buys a birthday present for Lavinia - a parrot. But while she goes out to buy some birdseed, Old Tom lets the bird out of the cage. Angela returns home to find Old Tom and Lucy chasing the bird around the living room. They almost catch it, but it escapes through the chimney. Then Lavinia arrives. Angela pleads with Old Tom and Lucy to catch the bird, while she keeps Lavinia busy. Old Tom and Lucy build a home-made flying machine so they can fly after the bird, but it keeps outsmarting them. Finally, Old Tom catches the bird with his net, but he falls out of the flying machine. The bird and Old Tom tumble down Angela's chimney and land back in her living room. Lavinia is delighted with her present but, because she believes animals should be free, lets the bird go.

The Queen, wanting to see someone different at her next garden party, choses Angela and Old Tom at random. Angela is delighted, but gives Old Tom a crash course in manners, just in case. The garden party begins, but the Queen doesn't want to go, because her dog doesn't seem well. Meanwhile, Old Tom upsets several party guests and seeks refuge from them in the palace. There he annoys the Queen's dog, which chases him around the throne room. The Queen enters and, delighted to see her dog full of life again, decides to go to the garden party after all - with Old Tom as her guest of honor.