Oscar Moutz is a lucky soul! This notorious and clever villain has just escaped and evades the police by running off to prehistoric times with the aid of a time door carelessly left open by Mot. This mafioso finds the paleolithic age absolutely great and immediately installs himself as the king of "Halted History". Naturally, by forbidding any progress he can be quite sure that none is going to invent school, the law court or the police. While Oscar is thrilled, Leo is horrified by his stone-age family. A helping hand from Mot is called for in order to capture the bandit and get Leo's universe back to normal.

Leo's parents have just returned from Egypt, bringing back serious sunburns and an authentic sarcophagus of a cat, which the ever deft Mot manages to crush immediately. Cutting short Leo's rage, the monster swiftly sets off for ancient Egypt, the only place where one can find an identical cat sarcophagus, ferocious guards, mourners wailing like Tyroleans, a psychopathic High Priest and a neurasthenic Pharaoh. The difficulty here is not so much finding the way through the labyrinthine corridors of the pyramid, but rather trying to raise a laugh from the Ruler of Egypt, whose life is nothing but a vale of tedium.

December 31st: party time! And Leo's parents are throwing a costume party. Finger food, music, dancing and fun, is more than one needs to attract Mot. Turning up unexpectedly, the monster mingles with the guests who consider his costume to be a great success. One small problem: Mot can't hold his champagne! One tiny sip is enough to send the monster into a strange torpor punctuated by violent hiccups which transport the house through the centuries. New guests gush from every epoch: an enterprising Bedouin, a stunned medieval samurai, an annoyed gorilla, etc. The only one not enjoying himself is Leo who is preoccupied with trying to avoid disaster and awaken Mot.

Colonel N's day of glory! This eccentric officer has manages to kidnap Mot! The monster's powers will allow him to realize his dream: to travel back in time in search of the most ferocious warriors. In the military laboratory, a platoon of soldiers is at the ready and the experiment can begin. Destination: Mongolia, 1230. Their mission: bring back the Huns, the most merciless barbarians of all time. Unfortunately for Colonel N, his squad returns with one very small Hun as all the rest had left to invade Europe. For Leo, the hardest part is not saving Mot and the tiny barbarian but rather, convincing his parents that the tiny Hun is his Bulgarian pen-pal ....

It really is more fun playing bows and arrows in the Middle Ages than doing maths, isn't it? Glued to his desk by some tricky geometry homework, Leo is trapped for the afternoon. Not to worry, Mot always has a solution. All he has to do is transport his friend to tomorrow so that he can collect the answers and bring them back to today in order to complete his work. The result: homework completed in five minutes and the afternoon free. Simple, isn't it? All this type of voyage calls for, is a little bit of accuracy - a subject Mot neglected to revise. Left reluctantly pacing the corridors of time, Leo wanders between his childhood and the centuries while Mot guzzles anti-freeze.

It's show-time for Leo! This evening in the school play he is to play the role of the wizard. For the time being, he is in his room rehearsing and it isn't going too well. Luckily Mot brings him back a role-model: a real wizard! Ralph Machinello! The best of the Middle Ages, or so they say ... With all the good will in the world, Ralph drones a series on incantations with unexpected and disastrous consequences. A booming Swiss cuckoo bursts forth from the neighbor's throat, Aunt Zelda becomes a horrifying virago, Mot is Leo, Leo is Mot, and Ralph is a bat who must be caught if ever one is to undo this surfeit of spells.

Feverish, Leo's father is suffering from a major attack of flu. He tosses in his bed beneath the myopic gaze of Dr. Meurz who requests some ice for the poor man's fevered brow. Mot, with much good will and clad in a nurse's uniform leaves immediately for the North Pole. Upon arrival the Tellurian is frozen by a violent blizzard and so neglects to close the time doors. Ice floes and penguins spill into the house. The myopic doctor frantically auscultates a sea-lion. A Russian submarine moves about in the bedroom. Battling alone against this torrent of catastrophes, can Leo save his father from the jaws of a polar bear and defrost Mot whose head occupies the vegetable crisper in the family fridge?

Under the glare of the spotlights, Diane, fifth chorus girl in a toothpaste commercial, assisted by Leo the devoted trainee, begins her career as a star. On the set are Tarzan and Jane, the heroes of the commercial who are praising the merits of fresh breath. Ready to win his first Oscar, Mot bursts into the studio armed with his acting talent and a five ton elephant ridden by two Englishmen who are keen on using exploding bullets on safari. Total destruction of the sets and also the career of Diane, whom Leo will have a hard time winning back. Especially as the scene is broadcast live ...

A woman preaching dietetics - a dinner rich in fiber and low on animal proteins - is enough to make Leo's father, just gone to bed after a low-fat meal, dream of giant hams spotting a landscape of pizzas the size of lakes. This is where Leo and Mot come in. The duo have to deal with a father who dreams that he is Rambo, machine-gunning anything that moves with lengthy bursts of olives. Escaping Dad's rather macho dream, Mot and Leo go from dream to dream, passing through the neighbor's secret world to Zelda's dreamy trance, from romantic violins to the fury of a disco with a floor of undulating waves ...

Mot has made an amazing discovery: a Roman gladiator who is Leo's exact double! The monster takes Leo to see for himself. Arriving in the middle of the Coliseum, Leo is completely floored: there is his double being chased by a raging bear. The adolescent is horrified and the monster is categorical: there can be no question of saving the twin. If one plays around with the past, one alters the present and then anything can happen. While his parents and the television speak Latin, Leo is stuck in Rome as a very mediocre gladiator and his double undergoes a stormy session of psychoanalysis in the twentieth century.

Arthur Squale, a mercenary hunter with an exceptional sense of smell, is hired to find Max, a superb parrot who has escaped from the zoo. Guided by his nostrils, Squale arrives at Leo's where Max has taken up residence. Sticking out of a wardrobe is Mot who, having been imprisoned by a Hindu trap, asks Leo for emergency aid. Leo grimaces at the idea of missing a basketball match on TV. Max is occupied with the telephone, and places order after order, attracting delivery men, mafiosi and bunnies to the house, where Squale haunts the tiniest recesses, gun in hand, ready to anesthetize Mot. The olfactory hunter is in seventh heaven - it is not every day that one stumbles upon an unknown species and spends the afternoon having doors smashed into one's face.

If you want to forget a frustrating love affair, there is nothing like a good session of snow surfing in the Himalayas. So, Mot and Leo are surfing on the Tibetan slopes when they run into a Yeti. Propelled into a time fault by the collision, Leo, Mot and the Yeti pop out of the neighbor's fridge. Mot and Leo both agree that the Yeti must return to its native Tibet. The route is simple: first stop, the Tyrol, then a stop-over at a Savoy cable-way and a lay-over at the municipal ice-rink where Diane is hoping to win the figure skating competition. The Yeti, a dark horse and amazing dancer, dumbfounds the jury by his skillfully tango on ice.

The golden city really does exist! Félipe Cortez, conquistador, and Ramon, his henchmen found it! Leaving their century and entering ours via Leo's wardrobe, Félipe and Ramon have hit the jackpot on "Win Your Weight in Gold", the game show for cultured viewers. Taken in by Leo's parents, who mistake them for Mexican tourists without passports, our two lost souls are going to be with the family for quite some time. The father is furious as every morning Cortez steals his bathrobe and Ramon tries to break down the door to Leo's wardrobe.

Leo is a fan of "Starflash", the star of science-fiction. So, the ever-helpful Mot decides to take him into the film. The situation becomes complicated when they want to get out, especially if they have to exit through a horror film that ends up taking over the entire house. It's only natural that the parents are transformed into monsters by a Z film Mad Scientist, and that the father's head rolls under the armchair while mother tries to reassemble the other scattered pieces of her husband. Luckily, the lady next door is a genius with faulty VCRs ...

Leo is warming up. He's going to lost the race against Rocco. The worst part is that Diane is going to the movies with the winner. Mot arrives in time to make Leo jump through time - then seconds later - to the finish-line, in front of the show-off Rocco ... Bad luck! Mot transports his friend to a parallel universe, a world very similar to ours but with one little difference. It is a world where Leo's parents had a daughter! Léa! It's going to be tough for Leo to run in pumps, even without counting on Rocco, who is in love with Léa, to whom Leo, squeezed into a dress, bears a strange resemblance...

Pandemonium in the House! Everything must be just right and watch your language because Mr. Yuyu is coming! This nice Japanese gentleman who is forever smiling is Dad's most important client. Mr. Yuyu has long dream of knowing the customs and home life of a typical family in our fair land. He is not going to be disappointed and will leave convinced that every western home contains the following: a hysterical aunt, a right-angled dachshund, a playful child armed with an electric rifle, a hairy and hungry monster who can change himself into anything at all, a byzantine harem complete with traditional orchestra on the master bedroom, and a father who is a collection of tics ...

Leo is having trouble with Diane: the emotional woes of youth. Fortunately Mot arrives with Rita Glamour, a specialist in matters of the heart. A good love potion will do the trick, except when Mot is the one who drinks it and the falls in love with Leo. Leo's running away in order to escape the attentions of his big buddy, somewhat disturbs the sunbathing of mother and Zelda. As for Diane, she is swiftly engulfed by a wave of jealousy. Who indeed is this invisible rival who does nothing but shout declarations of love for Leo?

Lovers of universal peace come to the island of Poto-poto! There you can touch the Mizu, a funny ball of fur that will plunge you into an idiotic trance for quite some time. Brought back by Diane and Mot, avoided by Leo, fondled by everybody; the Mizu rages trough town, spreading a contagious and idiotic joy. Zelda discovers a sudden fondness for the father, whom she crowns with roses, the mother shares a culinary friendship with the lady next door, while Diane who is drunk with joy and astride a back of a vacuous Mot, gallops across the lawn. Protected by his household astronaut's attire, will Leo be able to capture the Mizu?

Augusto Freezer makes his living by supplying the galactic zoos with innocent creatures torn form their native lands. Big-hearted Mot involves Leo in an inter-galactic rescue mission. And that is how squealing, furry space creatures are transported from a space ship to Leo's bedroom, just in time to disturb a reconciliation ceremony between Leo's parents and the lady next door. What can one lone adolescent do to reanimate a frozen neighbor, hide a motley assortment of extra-terrestrial creatures and finish his homework, all in one afternoon without his parents noticing that anything is amiss.

Igor Reflex, a robust detective specialized in delicate investigations, is hired by the lady next door to spy on Leo's family. In contact with the curious middle-aged woman by microphone and earphone, Igor gets into the house and supplies on-the-spot-reports. Passing from a wardrobe to a camp of Navajo head-hunters in order to get to the corridor, before being chased by some sinister Chinese guards, the private detective must keep the avid neighbor informed while resisting the amorous onslaughts of Zelda, who is just crazy about this seductive cousin. Leo and Mot are far too busy voyaging through time seeking the ingredients needed to make the cocktail of the century, to notice any of these goings on.

The walls swallow up any monster who happens to pass near them, the stairs grow into cliffs, the kitchen shrinks and the carpet roars with breaking waves. It's hell at home! Leo can't understand a word of the messages sent by Mot, who is stuck in a dimension of unknown geometry, traveling from the microwave to the TV, via the bathroom mirror. Mother claims a restive sofa while father asks himself how he is ever going to get out of there. Perhaps if one could attach oneself to the ceiling of the corridor without being roasted by jets of lava from the raging carpet ...

Diane, Leo and his family are on an educational holiday in a typical village of the Middle Ages, restored at great cost, smack in the middle of beautiful parking lot. Mot is jealous because he was not invited and forgets to close the time doors behind him. Without the least effort, the parents find themselves in the real Middle Ages, involved with the local lord, Robert the Brash. The father, who is convinced that he is participating in a detailed and careful reconstruction, flabbergasts his wife by taking part in a manly tournament and a torture session which is surely a subsidiary test. While trying to find his parents, Leo voyages between the present the past and the wrath of Diane.

It isn't easy to prepare a report on a Quatrocento painter when you have no reference material! Luckily, Mot knows a guy named Leonardo, an obscure Florentine dauber of the sixteenth century. Not knowing that they are followed by Diane, the two friends arrive in the artist's studio to find him busy with his model, Mona. Unfortunately, Diane remains stuck in the Renaissance, while in their living room the parents become acquainted with Mona's violent temper. Of course, the situation is not really serious, as the time path for bringing Diane back couldn't be simpler: all you need to do is go through (among other things) a viking birthday and the coronation of Elisabeth II. To get back, just take a left after Noah's ark ...

Rewrite all the history books! Assyria had a blond king and nobody knows it! In order to help out his chum Mot and avoid a sinister double-boiler for Zozi, an ancient and cowardly Magus, Leo becomes the Master of Assyria. Having all this power is going to be tough. Should one have drawn and quartered absentee civil servants or decapitate the owners of messy dogs? Not to mention the fact that a war was provoked and history was turned upside down when one refused to marry a 120 kilos princess, and so on. In the meantime, all that isn't going to tell us where to find the Marrakech Turbot.

Leo is not having fun! His head teacher is in the living room with his parents for a severe look at Leo's school record. While Leo is in his room, trying to look his best for the occasion and getting ready to go down, Mot arrives with some strange colored marbles, which Leo takes to be chewing gum and immediately swallows. The result is devastating. Leo goes through every stage of rubbery metamorphose, and is going to have a hard time allaying his parents' suspicion and finding a way out of the situation. Not to mention the fact that his hand is roving about the neighbor's place, that Mot is also affected by this phenomenon and that Diane, his only hope, has just swallowed a blue marble ...

If ever Mot asks you to look after the gifts destined for the love of his life, don't do it! Otherwise - Rex will drag your house around the globe, three monsters will spray the surroundings with great blobs of green saliva while a furious shark destroys your plumbing. While Mot takes a leisurely shower, unaware of the total devastation, Leo is rather busy: Zelda is a noisy parallelepiped, cubic planes fall on a square earth and the 2.30 express bears down on the house. When Molly finally asks him if he has maybe overdone it, there, standing in the middle of the room is a stiff crocodile in a checkered suit who cannot help but agree.