John Smith (Alex Pettyfer) is an alien from the planet Lorien. He was sent to Earth as a child with eight others to escape the invading Mogadorians, who destroyed Lorien. Here, John is protected by a Cepan, or guardian, Henri (Timothy Olyphant). Together, they live in a beach-side bungalow in Florida.
When the film opens, a St. Bernard puppy and a large group of others are stolen from a pet store by two thieves, Harvey (Oliver Platt) and Vernon (Stanley Tucci). After meeting a dog during his escape from the thieves, the St. Bernard sneaks into the home of the Newton family. The workaholic father, George Newton (Charles Grodin), doesn't want the responsibility of owning a dog, but his wife, Alice (Bonnie Hunt), and their children, Ryce, Ted and Emily, convince him otherwise. While trying to name him, Emily (Sarah Rose Karr), plays a portion of Ludwig van Beethoven's Fifth Symphony and he barks along: thus they name him "Beethoven."
Jesse "Jess" Aarons (Josh Hutcherson) is a twelve-year-old aspiring artist living with his financially struggling family in Lark Creek. He rides the bus to school with his little sister May Belle (Bailee Madison), where he avoids the school bully Janice Avery (Lauren Clinton). In class, Jess is teased by classmates Scott Hoager (Cameron Wakefield) and Gary Fulcher (Elliot Lawless), and meets new student Leslie Burke (AnnaSophia Robb). At recess, Jess enters a running event, for which he had been training at home. Leslie also enters and manages to beat all the boys, much to Jess' irritation. On the way home, Jess and Leslie learn that they are next-door neighbors.
Mowgli is living in the Man Village with the girl who lured him in, Shanti, his adopted brother Ranjan, and their parents. However, Mowgli longs to return to the fun of the jungle, and after nearly leading the other children of the village into the jungle, is punished by his adopted father for trying to lead them into danger. Meanwhile, in the jungle, Shere Khan has returned to Baloo and Bagheera's part of the jungle to exact revenge on Mowgli. Baloo sneaks into the Man Village and gets Mowgli to come with him to live in the jungle; however, unbeknownst to them, Shere Khan also infiltrated the village, only to be chased off by the village people. In the ensuing chaos of the tiger's attack, Shanti and Ranjan go into the jungle to retrieve Mowgli, believing that Baloo is a hostile animal and kidnapped the boy.
In Edwardian-era London, in the nursery of the Darling home, Wendy Darling (Wood) tells her younger brothers, John (Harry Newell) and Michael (Freddie Popplewell), stories that enthrall Peter Pan (Jeremy Sumpter) and his fairy friend Tinker Bell (Ludivine Sagnier). Life is disrupted when their Aunt Millicent visits the family. Judging Wendy to be an "almost" full-grown woman, Aunt Millicent advises Mr. and Mrs. Darling to think of Wendy's future, saying that Wendy should spend less time with her brothers and more time with her as she learns how to be a proper young lady. The very idea terrifies the children.
When stroke victim Violet Kellty dies in her isolated cabin in the North Carolina mountains, Dr. Jerome "Jerry" Lovell (Liam Neeson), the town doctor, finds a terrified young woman (Jodie Foster) hiding in the rafters of the house. She speaks angrily and rapidly but seems to have a language of her own. Looking at Violet's Bible, Jerry finds a note asking whoever finds it to look after the woman, who is Violet's daughter Nell. Sheriff Todd Peterson (Nick Searcy) shows Jerry a news clipping from which Jerry surmises that Nell is indeed the dead woman’s daughter, conceived through rape.
Attorney Mitch Martin (Luke Wilson) breaks up with his girlfriend when he accidentally discovers that she takes part in orgies. Mitch encounters his high school crush, Nicole (Ellen Pompeo), at the wedding of his friend Frank (Will Ferrell) and makes an awkward impression. Later, he finds a house located near the campus of the fictional Harrison University in New York.
Alone in her home, the religion-obsessed Margaret White (Julianne Moore) gives birth to a baby girl. She at first intends to kill the infant, but changes her mind. As a teenager, her daughter Carrie (Chloë Grace Moretz), is a shy and isolated student at Ewen High School in Maine.
In 1999, Pierre Morhange, a conductor performing in the United States, is informed that his mother has died before a concert. After the performance, he returns to his home in France for her funeral. An old friend named Pépinot arrives at his door with a diary which belonged to their teacher, Clément Mathieu. They proceed to read it together.
Ludo Decker (Schweiger) is a Berlin based yellow press reporter. With his photographer Moritz, his daily routine is to spy on celebrities for the tabloid Das Blatt. He also uses his work for frequent sexual contacts with his objects of interest.
The film starts off with a rocket carrying two boys and a robotic dog: Jimmy Neutron (Debi Derryberry), Carl Wheezer (Rob Paulsen) and Goddard (Frank Welker). Jimmy is attempting to launch a communications satellite made out of a toaster, hoping to communicate with an alien species he believes exists somewhere out in the universe. Unknown to anyone, the satellite is picked up near the planet Yolkus, home to an alien race called the Yolkians. King Goobot V (Patrick Stewart) and his assistant, Ooblar (Martin Short), watch a pre-recorded message from Jimmy, featuring him introducing himself and explaining about life on Earth.
On Halloween in Haddonfield, Illinois, having already shown signs of psychopathic tendencies, 10-year-old Michael Myers (Daeg Faerch) murders a school bully. Later that night, he murders his older sister Judith (Hanna R. Hall), his mother’s abusive boyfriend Ronnie (William Forsythe), and Judith's boyfriend Steve (Adam Weisman). Only his baby sister, Angel Myers, is spared. After one of the longest trials in the state’s history, Michael is found guilty of first degree murder and sent to Smith's Grove — Warren County Sanitarium under the care of child psychologist Dr. Samuel Loomis (Malcolm McDowell).
The first day of Greg Heffley's middle school ends negatively; he learns about the Cheese Touch which is a rotten piece of cheese on the basketball court which everyone avoids, discovers the ups and downs to the school, and his best friend Rowley Jefferson (Robert Capron) embarrasses them both. He plans to become extremely popular, which results in two humiliating defeats joining the wrestling team by a weird, low popular kid named Fregley (Grayson Russell) and his arch-enemy Patty Farrell (Laine MacNeil). Later. Greg makes it an effort to make Rowley popular by changing his style of clothing and looks, and they also encounter delinquent teenagers at Halloween night in which they challenged.
The Heffley family attends a pool party at the local pool, where the family meets a former trouble-making friend of Rodrick (Devon Bostick) who is now a model student after attending a military school known as Spag Union, into which Greg's dad Frank (Steve Zahn) thinks about joining Greg.
The Heffley family attend a party at a roller rink, where Greg (Zachary Gordon) reunites with Rowley (Robert Capron), meets a new girl at school named Holly Hills who Greg instantly has a crush on, and reveals he passed on the Cheese Touch. Rodrick interferes with the party, embarrassing Greg as he describes his summer and the flaws between his brothers.