Sherlock Chipmunk is an episode of the ALVINNN!!! and The Chipmunks series.
Jeanette and Eleanor act as Sherlock Holmes and Watson when Theodore's teddy bear mysteriously disappears.
Theodore and Talking Teddy are working on being crime fighters though after Alvin's attacked by them, he learns that Teddy can't be a good crime fighter as he has a lame costume. Theodore confides in Dave that all he wants for his birthday is a costume for Teddy. Later, when the youngest Chipmunk is looking for his bear, he finds him missing and tells The Chipettes hoping for help finding him. Jeanette, currently interested in the Sherlock Holmes mysteries, enlists the assistance of Eleanor to solve the case. Their first suspect is Alvin, and while Eleanor takes a more direct approach with him, Jeanette looks for evidence, finding something sticky where the bear was last seen. During her investigation she questions Dave, inspects Simon's shoe, and discovers what the sticky substance was where the bear disappeared. She finds jars of the jam in the Seville kitchen and recalls seeing Miss Croner with the same jars. Holmes finds footprints to the elder's home belonging to Simon and decides to question him, learning he was donating old stuff to charity and returning a tool. They travel back to Miss Croner's house, and as Eleanor distracts her, Jeanette sneaks inside to find the jam and the bear's hat. Hearing Alvin in distress, Jeanette rushes to Eleanor and the two confront Miss Croner learning that Alvin made a deal with her to eat some of her jam if she made Teddy a superhero costume. During his party, Theodore loves the costume as well as the jam sandwiches Alvin was meant to eat.
- "Sleepless Nights" 
- This is the third time in the franchise that Sherlock Holmes has been portrayed: the first time being The Cruise from the Alvin and the Chipmunks series and the second time being Elementary, My Dear Simon from The Chipmunks series. Both prior episodes show Simon and Theodore playing the roles of Holmes and Watson while this episode is the first time that Holmes and Watson are being portrayed by The Chipettes.
- Theodore's superhero costume, first worn in the season one episode Super Heroes, makes its first re-appearance. Talking Teddy also makes another re-appearance.
- The fact that Theodore is seen celebrating his birthday alone would suggest that The Chipmunks are not triplets.