Dave is having trouble keeping up with the boys and having a romantic life at the same time. As a result, he puts out an ad for a nanny, but the boys keep driving them off. He finally hires a nanny named Gertrude, who is very punctual. The Chipmunks' new nanny is driving them crazy so to get her off their backs, the boys must convince Gertrude's boyfriend Bill that Dave is not interested in Gertrude so Bill will marry her. The brothers urge Bill to go racing to get her back. When the boys and Bill crash, they win Dave and Gertrude over.
- "Crazy Little Thing Called Love" originally performed by Queen.
- The title is a spoof of the film The Trouble with Harry.