Two years after taking in the Chipmunks ,
Dave Seville is injured when a cardboard cutout of Alvin sends him flying across the stage during a charity benefit concert in Paris. While he recovers in a French hospital, Dave asks his aunt, Jackie, to look after
the Chipmunks, Alvin, Simon, and Theodore. Arrangements are also made for them to attend West Eastman High School. After Jackie falls down the staircase in her wheelchair and also has to be hospitalized, the Chipmunks are left in the care of Toby, Jackie's grandson and Dave's cousin. Ex-JETT Records chief executive
Ian Hawke, who is broke and destitute after losing the Chipmunks, lives in the company's basement. Three singing female chipmunks, Brittany, Jeanette, and Eleanor (
the Chipettes), emerge from a
FedEx package. They meet Ian and tell him they mailed themselves there because they want to work with the man who made the Chipmunks famous. Seeing how well they can sing, he signs them up in order to resurrect his career. He also lies to the girls by telling them that the Chipmunks completely disrespected him and left him the first chance they got. While at school, two jocks bully the Chipmunks. The group is summoned to the principal's office after attacking and defeating the jocks. The principal, Dr. Rubin, a fan who saw them in
Denver, enlists their help to raise money for the school's music program by participating in a contest. A shocked Ian finds that the Chipmunks will represent the school; he also enrolls the Chipettes there. When the Chipmunks meet the Chipettes, both groups are smitten with each other, but the girls recall that Ian said they are untrustworthy, and the boys struggle to make it through a rehearsal because of their new crushes. Ian smugly walks in and introduces his new stars, the Chipettes, shocking the Chipmunks to see them working with him. A rivalry emerges when Ian convinces Dr. Rubin to let the Chipettes compete in the competition, and set up a concert for the two groups to compete to represent the school. Alvin becomes popular with the jocks and joins the
football team, inadvertently missing the concert. At the concert, Theodore and Simon withdraw, so the Chipettes win by default. Arriving to an empty auditorium, Alvin is called out by Brittany for his lack of responsibility. Alvin returns home and unsuccessfully tries apologizing to his brothers. Theodore runs away to the
Los Angeles Zoo the next day to live with a meerkat family, but finds a
wedge-tailed eagle living in their former exhibit. Alvin and Simon save him from the eagle, and the three reconcile. The Chipettes learn that they are to perform as an opening act for a
Britney Spears concert on the same night as the school contest. Ian convinces them to call off the battle and perform at the concert but refuses to give the same credit to Jeanette and Eleanor that he gives Brittany, who demands that they all perform together or not at all. Ian threatens to send them to a barbecue restaurant unless they perform. Before the school contest, Alvin receives a distressed phone call from the Chipettes, who inform him that Ian has locked them in a cage. He goes on to rescue them on his toy motorcycle while Simon tells Jeanette how to pick the lock over the phone. Simon and Theodore are on the verge of performing by themselves until the others arrive in the remote-control toy helicopter that Ian uses to chase them. The Chipmunks and the Chipettes perform together for the first time and win the money for the music program. Dave, who had left the hospital upon learning that Toby was looking after the Chipmunks, returns during the contest, happy to see the Chipmunks again, and allows the Chipettes to stay with them. ==Cast==