Rémy (Patton Oswalt) lives in a rat colony in the attic of a French country home with his brother Émile (Peter Sohn) and his father Django (Brian Dennehy). Unlike his kin, Rémy is a gourmet whose keen sense of smell is used by the colony only to detect rat poison in food. But Rémy yearns for more, sneaking into the kitchen to read the cookbook of his hero, Parisian chef Auguste Gusteau (Brad Garrett), who appears to Rémy in visions throughout the film to expound on his motto that “anyone can cook.” Rémy learns that Gusteau died after a harsh review from mean-spirited food critic Anton Ego (Peter O’Toole).
The rats flee the house when the resident, an old woman, discovers the colony. Rémy, separated from the others, floats in the storm drains to Paris on Gusteau’s cookbook, following the chef’s image to his namesake restaurant, now run by former sous-chef Skinner (Ian Holm). As Rémy watches from a kitchen skylight, Alfredo Linguini (Lou Romano), a young man with no culinary talent, arrives and is hired on at the request of his recently deceased mother to do janitorial duties. The boy, unknown to all but his mother, is in fact Gusteau’s son. Linguini spills a pot of soup and attempts to cover up his mistake by adding nearby random ingredients. Horrified by Linguini’s actions, Rémy falls into the kitchen and though desperately trying to escape, cannot help but stop and attempt to fix the ruined soup. Rémy is caught in the act by Linguini, who himself is caught by Skinner as he captures the rat, but not before some of the soup has been served. To everyone’s surprise the soup is a success. The kitchen’s sole woman cook, Colette (Janeane Garofalo), convinces Skinner not to fire Linguini provided he can recreate the soup. And thus begins an alliance, uneasy at first, by which Rémy secretly directs Linguini. The two perfect a marionette-like arrangement by which Rémy tugs at Linguini’s hair to control his movements and stays hidden under Linguini’s toque blanche.
Skinner discovers that Linguini is Gusteau’s son, which he hides to prevent Linguini from inheriting the restaurant, which would thwart his ambitions of exploiting Gusteau’s image to market prepared frozen dinners. Suspicious of Linguini, Skinner plies him with fine wine in an unsuccessful attempt to discover the secret of his unexpected talents. The next morning, hung over and disheveled, Linguini nearly confides his secret to Colette. Desperately trying to stop Linguini, Rémy pulls his hair, making him fall on Colette, leading the two to kiss. They begin dating, leaving Rémy feeling abandoned.
One night Rémy and his colony are reunited. Rémy argues with Emile and his father over his new career as a secret chef. In the process of scrounging food for the clan Rémy discovers Gusteau’s will which, after a chase by Skinner, he presents to Linguini. Linguini now owns the restaurant, fires Skinner, and becomes a rising star in the culinary world, attracting renewed interest from Anton Ego, who had written off the restaurant for dead. Linguini and Rémy have a falling out, Linguini deciding he no longer needs Rémy, and Rémy retaliating to the snub by leading a kitchen raid for his rat colony.
Things come to a head the night of a planned review by Ego. Linguini, unable to cook without the rat’s guidance, admits his ruse to the staff when Remy shows up, leading them all to walk out. Colette returns after thinking through Gusteau’s motto. Django, inspired by his son’s courage, returns with the entire rat colony to cook under Rémy’s direction, while Linguini, discovering his true talent, waits tables on roller skates. Colette helps Rémy prepare ratatouille, a dish so good that, in the climax of the film, a bite of the dish leads Ego to relive childhood memories of his mother serving him the dish as comfort food. Ego asks to meet the chef, but Colette tells him he must wait until the rest of the diners have left. At the end of the service, Rémy and the ratr are revealed. A changed man, Ego writes a glowing review, declaring that the chef at Gusteau’s is the greatest chef in all of France.
In the denouement the restaurant is closed by a health inspector, who finds the rats after being tipped off by Skinner. Ego loses his credibility and job when the public discovers he has praised a rat-infested restaurant. Everything is for the best, however. With Ego as investor and regular patron, Linguini, Colette, and Rémy open a successful new bistro called “La Ratatouille,” which includes a kitchen and dining facilities for both rats and humans.
The Walt Disney logo, like the company, has served as a beacon for decent family entertainment and worldwide recognition. The Walt Disney logo is a ‘stylized version of the founder’s signature’ that signifies the brand name and promises secure, cheerful and quality American mainstream entertainment.
Similarly, the Walt Disney signature with “World” added to it is used for the company’s resorts "Walt Disney World Resort", a Mickey’s head is adopted for the company’s Mickey Mouse Club and “Studios” was added to the Walt Disney logo signifying Disney Studios around the world.