Osmosis Jones - Plot

Plot

Frank Detorre (Bill Murray), a widowed slovenly zookeeper in Rhode Island's Sucat Memorial Zoo is the upset of his young daughter, Shane (Elena Franklin). He eats compulsively unhealthily and has no regard for germs or disease. While trying to eat a hard-boiled egg with mayonnaise and salt before a chimpanzee drops it in its filth, Frank picks it up and eats it, using the "ten second rule" as a justification for the unsanitary act.

Inside Frank's body, Osmosis "Ozzy" Jones (Chris Rock), an agent of the FPD, is a funny, adventure-seeking white blood cell and a rebel cop, frequently disobeying authority to do what he thinks is right. He grew up poor on the "South Side" of Frank and is often mocked by his fellow cops due to his rebellious nature. He has been relocated to the mouth to fight against germs entering the body via ingestion after he induced Frank to vomit all over Shane's teacher, Mrs. Boyd, which was considered a false alarm because he had been the only one to suspect an incoming pathological threat. After several newcomer germs, believed to be gingivitis, hijack a "squad car" there, Ozzy and his senior partner, who is piloting their helicopter, are pulled into the lungs by a massive yawn while in pursuit. After the germs evade capture and pass into "Immunity's" jurisdiction, Ozzy disobeys direct orders and continues the pursuit on foot. The germs escape and Ozzy accidentally triggers a major cramp in Frank's leg.

Meanwhile, as Frank's saliva cells work in the mouth to clear out the egg, a virus named Thrax emerges and goes to the left armpit to recruit some sweat germs for his big plan to launch a deadly infection with posing as a common cold while plotting something bigger. Meanwhile, Mayor Phlegmming is preparing for re-election, campaigning with the promise of more junk food and a trip to Buffalo, New York. His reckless policies are largely responsible for Frank's deteriorating health. In an attempt to cover up the severity of situation, Phlegmming "tells" to take a cold-suppressant pill which nicknamed Drix (short for Drixobenzometapetramine and his brand name Drixenol), arrives in the body and covers Frank's infected throat with a disinfectant to soothe the irritation. Ozzy is assigned as Drix's partner, much to his chagrin.

In the nose, Thrax starts his plan by flooding the nose with snot after Jones accidentally let a pollen ball get away. Back at Cerebellum Hall, the mayor threatens to send Jones down the next nosebleed if he can't keep quiet about a virus in the body. While Drix is offered a different partner, he decides to stay with Ozzy who has bad times and discovers why. Years ago, Frank ate some oysters off a kid's project at his daughter's science fair. Jones saw some remaining bacteria emerge, but feeling there wasn't time to call for back up, he instead hit the "puke" button. The results were bad: Frank lost his job, the teacher he puked on issued a 200-yard restraining order, and Osmosis got suspended and has been placed on out-of-the-way patrols ever since. Drix says that Jones was justified in his decision as oysters are a breeding ground for dangerous bacteria of any type.

They later learn from a reformed Influenza germ that Thrax is more dangerous than the average germ. His current whereabouts are a zit on the forehead. Posing as germs, Ozzy and Drix enter and discover Thrax's plot to overheat Frank's body, killing him from the inside. He wants to become the nastiest new virus, attempting to kill each new victim faster than the previous. His plan for Frank's death within 48 hours, breaking all of his previous records. Ozzy and Drix confront him in The Zit, where Ozzy launches a grenade of medication at him and his cronies, popping the skin blemish, killing nearly all of his men, and seemingly ending his siege. Frank, meanwhile, tries to persuade Mrs. Boyd to lift the restraining order so he can go on a school camping trip with Shane, but the zit pops onto her lip, making her refusal official. Back at the precinct, Phlegmming argues with Ozzy and Drix who are fired and ordered to leave Frank's body, respectively.

Thrax survives the explosion and, after killing off his remaining henchman for suggesting they lay low until they recruit help in larger numbers, decides to launch a lone assault on Frank's hypothalamus gland (the portion of the brain that controls temperature) by disabling its self-regulative capabilities. Arriving there, he uses his virus infecting finger to destroy the protoplasmic barrier around it, and retrieve a DNA bead. Soon after, Leah Estrogen, the mayor's less-oblivious secretary and Ozzy's love interest, discovers his work and alerts security. He manages to evade them; taking Leah hostage and escaping from the brain to the mouth. At the same time, Ozzy, in a movie theater showing dreams from the brain, discovers that Thrax is alive and in the brain when the screen colors turn a feverish red, and the dream he's watching becomes a nightmare with everyone laughing at Frank. He rushes to stop Drix from leaving the body and manages to convince him to help stop Thrax once and for all. Meanwhile, the temperature continues to rise, causing destruction all over the City of Frank.

Frank is taken to the hospital under the influence of Thrax's attack. Ozzy and Drix rescue Leah and confront him, who leaves Frank's mouth after causing confusion using pollen bombs. Ozzy is launched out after him by Drix. They fight for the DNA chain on one of Shane's eyes and end up in her false eyelashes, which she was wearing atop her natural ones. During the fight, Thrax threatens to break his own record by killing off Shane, but Osmosis causes him to get stuck on the false eyelash and escapes onto Shane's eye while Thrax falls into a vessel of alcohol below, where he dissolves.

During this time, the situation becomes even more dangerous when the temperature hits 108 degrees, causing Frank to go into cardiac arrest. Just as doctors give up, he is revived when Ozzy returns to him via one of Shane's tears with the chain that holds Frank's missing hypothalamus chromosome. Ozzy is reinstated into the "Immunity Force" with full privileges, he and Drix are declared heroes with the Chief of Police (Joel Silver) rehiring him, and Leah tells Ozzy that she loves him. Drix is allowed to stay in Frank's body with him. (Ozzy plans to get Drix a lawyer at the hemroid in order to extend Drix's time in the body).

Sometime later, Frank and Shane spend some long needed father-daughter time together on a hike. Frank has also since begun to improve his diet and personal hygiene. Meanwhile, Phlegmming has lost his position as mayor and now has a new job, cleaning the bowels as a janitor. He accidentally ejects himself from the body via the rectum by touching a button that is marked "DO NOT TOUCH!" which triggers flatulence. To this, Frank makes a joke on his health by saying, "Out with the old, in with the new."