 Once they set off on a nationwide coast-to-coast tour, Ian takes advantage of their naïveté by overworking them constantly.Frustrated by what Ian has done to the Chipmunks, Dave decides to infiltrate their concert to reunite with them.Before their tour can begin, a veterinarian explains to Ian that the Chipmunks' voices have worn due to exhaustion and suggests that they take a long rest, but as Ian doesn't want to cancel the concert and give refunds, he advises the Chipmunks to lip-sync.