The hero of the tale is an unnamed young man, a commoner. Puss is his female black cat. The hero is in love with the daughter of a king, and the feeling is mutual. Puss is in love with the white cat of the king, who also serves as the royal chauffeur. The king objects to both relationships and throws the commoner and his cat out of the palace. The rejected duo head to a movie theater, seeking entertainment. They watch a film featuring "Rodolph Vaselino" (Rudolph Valentino) as a bullfighter. The film inspires Puss to form a plan which will allow her master to win the hand of the royal daughter. But Puss first asks for a prize for her services, a pair of boots.
After a brief introduction to the principal characters, the film follows Asterix as he encounters a group of Roman legionaries in the forest. Despite being significantly outnumbered, Asterix leaves the Romans beaten and bruised for daring to interrupt his wild boar hunt. Their state upon their return to camp prompts the leader Phonus Balonus to seek the secret behind the Gauls' seemingly superhuman strength. Phonus selects a volunteer (by means of a single round of musical chairs) to pose as a Gaul in order to infiltrate the village; the unlucky loser is a short, slack-tongued misfit named Caligula Minus. He is dressed in a wig, false moustache and traditional Gaulish dress and led in chains through the forest as a prisoner, awaiting rescue by the Gauls. Sure enough, Asterix and Obelix free Minus and believe his flimsy cover story that he is a Gaul from Belgium.
The film centres on a girl who wants a dog. She brings home a puppy but her mother wouldn't let the puppy stay. The girl is upset and goes outside to the playground where all the other kids are walking their dogs. She starts playing with her mitten, pretending that the mitten is a dog. And the power of her imagination turns her mitten into a knitted puppy, which keeps the mitten red color and black spots on the back. The puppy starts chasing a cat which ends up finding shelter on top of the ad board saying "Everyone who has a dog is welcome to take part in the kennel club competition!" The girl takes her puppy to the competition and it completes the task better than other dogs but on the way to the finish one of the threads of puppy's knitted coat gets caught by a nail on the wooden barrier and it loses the competition. The girl takes it home and is about to feed it, when it turns back to a mitten. Mom notices the girl trying to feed a mitten and decides to get her a real puppy.
This is a story about a little hedgehog (voiced by Mariya Vinogradova), who is on his way to visit his friend the bear cub. As explained in the introductory narration, the two would meet every evening to drink tea from the cub's samovar, which was heated on a fire of juniper twigs. As they drank their tea, the hedgehog and the bear would chat and count the stars together.
The movie begins when Obelix falls in love with the chief's niece, Panacea. His heart is quickly broken when he hears that she is due to be married to the handsome Tragicomix. The two lovers are walking in the woods when they are captured by a group of Romans led by a fresh new recruit looking to impress the Centurion of the Roman Camp. The Centurion is infuriated, knowing that the Gauls will attack. Panacea, Tragicomix and the new recruit are sent to the farthest outpost of the Roman empire (in the Sahara) while the Centurion and his troops prepare for the battle.
Asterix and Obelix must travel to Britain with a barrel of Magic potion, to help a rebel village fight against the Roman Empire, which has conquered the whole country.
The film portrays the increasingly desperate efforts of Mr. Johnson, an old man, to rid himself of a small, yet extremely destructive, yellow cat that will not leave his home. The attempts to get rid of the cat become more comical, and the cat becomes increasingly destructive, until Mr. Johnson resorts to an explosive solution. Mr. Johnson tries to put the cat in the woods, but gets lost, and returns. He traps the cat in a sack to have a fish, and tries to put in the sea on a boat, but nearly sinks when he is attacked by fish. Mr. Johnson tries to put the cat in a balloon, and send him flying away, but flies away, himself, and returns, hurt. Mr. Johnson tries to take the cat away on a pump trolley on a railroad track, going over many damsels in distress, but jumps over a cow, and hits a bug crossing the railroad track, when he falls into a mine, only to be attacked by snakes, bats, and mice. Mr. Johnson tries to blow up the cat, but fails with his hair on fire, and explodes into an angel, only to tease the poor little cat, who is squashed by his human body. The result is a twist ending playing on the end of the children's song, with the cat's nine lives bedeviling Mr. Johnson for eternity.
The Romans plan to capture Getafix to keep him from making the magic potion. In an effort to rescue him, Obelix accidentally puts Getafix out of action with a menhir, the impact of which causes amnesia and insanity.
Littlefoot notices a longneck herd entering Great Valley, and informs his grandparents. They tell him that the longnecks are their cousins, and that they must go and greet them. As the Old One, the leader of the herd, tells the residents of the great valley that her herd has been migratory since a heavy rain period turned their old home into a marshland called "The Land of Mists", and became the home of many dangerous creatures, Littlefoot meets a longneck girl named Ali, and invites her to play. He introduces her to his friends, but as she is not used to associating with diverse species, she is afraid of them.
After a swarm of "leaf-gobblers" descends upon Great Valley, devouring all plants and leaving it a barren wasteland, the inhabitants must seek another place where they can survive until the plants in Great Valley have grown back. However, the Leaf Gobblers have left a path of devastation behind them, leaving no food for the dinosaurs to find. After searching for many days, tension enters the group as Cera's father and Littlefoot's grandfather argue over changing their course, which sparks a fight between Littlefoot and Cera. The fight soon breaks up when Cera's father announces that each herd will go its own way the next morning. Not wishing to be separated, Littlefoot leads his friends off in the night, in the hope they can find food before they are caught. They leave a trail for the grownups to follow, and eventually reach the "Big Water". Although they are disheartened by the undrinkable water, they spy a verdant island connected to the mainland by a thin land bridge. On their way, a tsunami occurs, which they narrowly escape. They quickly tuck in to the plentiful bounty of the island, but are then horrified to discover the tsunami has destroyed the land bridge.
Russia is being terrorized by an evil witch known as Baba Yaga (Andrea Martin), and the only one who is not afraid of her is Bartok the Magnificent (Hank Azaria). Bartok, an albino bat, has just arrived in Moscow and is impressing everyone with his performances, including Prince Ivan (Phillip Van Dyke). However, Ivan's advisor, Ludmilla (Catherine O'Hara), finds Bartok annoying and naive, and she tries to make a Cossack stop his performance. After Bartok's show, a bear suddenly attacks. Bartok saves everyone by stunning the bear, knocking it over, and trapping it in a wagon.
One evening, Petrie arrogantly begins telling a tale of the best creatures of the world: the Flyers. Cera disagrees and the tale isn't true. Petrie then spots a herd of dinosaurs visiting the Great Valley, but apparently they don't matter. The youngsters later went to bed after their parents called them in for the night. Later that night, Littlefoot sees a strangely blue colored meteor falling from the sky and colliding into Threehorn Peak, a volcano in the Smoking Mountain range. When Littlefoot describes it the next morning, most of the adult dinosaurs in the Great Valley disbelieve Littlefoot's story since he is a known liar. However, two newcomers, the mysterious and racially-insensitively named "Rainbow Faces", speak eloquently of possibilities of wonders beyond what they know. The Rainbow Faces suggest (i.e., lie) that the rock may be a "Stone of Cold Fire", a stone possessing magical properties. Pterano, the devious, sinister and outcast uncle of Littlefoot's friend Petrie, somehow overhears the conversation and conspires to use the rock to take control of the Great Valley Ganon-style. Pterano asks Petrie, who idolizes him for some reason, for the location of the rock and is told it has landed on Threehorn Peak. Littlefoot's friend Ducky overhears Pterano's plan because dinosaurs apparently aren't good at whispering, but Pterano and his cronies, Sierra and Rinkus, abduct her before she can warn the others. They take her along as they set out to find the Stone of Cold Fire before an Amber Alert is filed. The other dinosaurs discover Ducky's kidnapping. The adults tell the young ones that Pterano had been made an outcast due to his carelessness after self-appointing himself leader of a group of dinosaurs; while searching for the Great Valley, Pterano was overconfident and led his followers directly into a pack of small, albino Sharpteeth. Pterano, a Pteranodon like Petrie (that makes sense; they are uncle and nephew), was able to fly away, although the event left him heart-broken. He ended up expelled from the herd as punishment for abandoning his followers, yet he continues to hang around undeterred.
Ducky is upset with her brother Spike, for keeping her awake at night with his snoring (called "sleep rumbling" by the characters), and for eating her treestars. She tells Cera about her feelings, and confides that she does not know how to express them, even though they have lived together for eight movies, to which Cera agrees to teach her. Yes, that's right. Angry Cera who storms off like every other movie is going to be the emotional guide. At the same time, the children are attending an unaccredited school of sorts, in which they are taught by an old Pachyrhinosaurus named Mr. Thicknose, who falsely professes to have been everywhere and seen everything. Littlefoot is eagerly questioning all the topics they cover, to the old dinosaur's irritation, and blows the top when he startles Mr. Thicknose into running into a tree, upon which a melon falls on his head. Mr. Thicknose complains to Grandpa Longneck about Littlefoot's behavior, and Grandpa Longneck, knowing Littlefoot meant no harm, gently explains to him why he must be more respectful to Mr. Thicknose.
After a period of harsh rain, the Great Valley is partially flooded and covered in debris. Littlefoot rushes to find his friends after the storm ends, but they are preoccupied: Cera and her father are removing a large log from their nesting area, Ducky and Spike are relocating their nest with their family, and Petrie has gotten a cold. Littlefoot is bored and instead of helping his friends clean up the dead bodies he selfishly wishes for a brother (a wish that will be granted in the next movie, although ironically they will not get along). Eventually he explores on his own and discovers a large area flooded by the rains. The adults advise their children to stay away, fearing creatures from the outside may have been washed into the Valley. However, Littlefoot thinks he knows best so, ignoring the advice, he goes anyways and meets Mo, a playful young "swimmer" that had been caught in the floodwater.
Littlefoot has nightmares which involve the "Great Circle". He mentions it to his grandparents, who share the same psychedelic trip. Grandpa has a "feeling" that he wants to "go somewhere", and they leave the "next day" with only their gut feeling to guide them. Out of curiosity, Cera, Spike, Ducky and Petrie follow him, starting after them the following night. New characters are introduced throughout the film: Sue (Bernadette Rostenkowski-Wolowitz), a Supersaurus, who is driven on by the same sense as Littlefoot and joins his journey. Sue towers above all other longnecks and one day wishes to meet someone taller than herself. Meanwhile, Littlefoot's friends meet Pat (James Garner), an elderly Apatosaurus. He is slow-moving and even scalds his hind foot whilst crossing a magma river, but does arrive at the crater in time for the event.