In this CG/live-action hybrid film based on the 1950s cartoon series of the same title, three chipmunk brothers - Alvin (Justin Long), Simon (Matthew Gray Gubler), and Theodore (Jesse McCartney) - head to the city, where they meet songwriter Dave Seville (Jason Lee) who is down on his luck. They invade his house and shock him with their ability to talk, but thats not all: they can also sing in harmony. So Dave's gets inspired and writes a song, which turns the trio into overnight sensations.