Dave suffers a bump to the head and forgets who he is. After seeing a commercial hawking a book on hipness "for those who do not know who they are", Dave buys the book and after reading it becomes a trendy, hip man. After seeing the Chipmunks, he thinks they are wild squirrels! Dave cannot identify Theodore, Alvin or Simon, and as such feels no responsibility to be their guardian. When Simon deduces Dave has amensia, he says they must act fast to jog Dave's memory or else they will be out on the streets. Each Chipmunk brings up memories of Dave, but he fails to reconnect. They later try to join in on Dave's hip activities to show he is part of them, but women see the Chipmunks more as cute pets. Finally, the saddened Chipmunks figure they ought to leave. Even as Theodore is visibly upset, Dave does not connect, focusing on what to wear to a power lunch. A portable video game drops out of Alvin's backpack, the same one that fell and hit Dave on the head earlier. Dave begins yelling to shut it off, he cannot stand the noise. The Chipmunks express hope that Dave may be coming around, until Dave lets out his signature "ALVIN!" shout. Dave, his memory restored, angrily grounds the Chipmunks. When they dance in glee, he cannot understand why they are happy to be grounded, only the Chipmunks were glad Dave is back.
- "Hip and Happenin'"
- In one attempt to get Dave to remember himself, Alvin plays the piano instrumentals classic Chipmunk songs to include "Christmas Don't Be Late" and the theme song "We're the Chipmunks". Unfortunately, the amnesiac Dave remarks "know any George Michael"?
- As of right now, this episode isn't available in English.