The tree that the chipmunks Alvin, Simon, and Theodore live in is cut down, and driven to Los Angeles. After JETT Records purchases it as a Christmas tree, the Chipmunks meet the struggling songwriter and composer, David Seville, who has had his latest song rejected by the company’s chief executive, Ian Hawke, his former college roommate and best friend, who claims that there is “no sense in writing songs that no one is ever going to sing.” Dave also once had a relationship with his next door neighbor, Claire Wilson.
In the process of escaping the JETT building, the Chipmunks hop into a basket of muffins Dave stole from one of Ian’s coworkers, and follow him home. Once there, Dave discovers the Chipmunks and kicks them out, only to hear them sing “Only You (And You Alone)”. He then makes a deal with them; they sing the songs he writes, and he provides food and shelter for them. Unfortunately, when Dave tries to present the Chipmunks to Ian, they fail to sing to him on account of stage fright. The day worsens as Dave is dismissed as the Chipmunks ruin his job presentation by having drawn on it, thus getting him fired from his job. When Alvin tries to set the mood for Dave’s dinner with Claire, things become peculiar, and she rejects Dave after he tells her about the Chipmunks. To make it up to Dave, the Chipmunks go to Ian in an attempt to obtain a record deal.