David receives a voice recorder on his birthday, as Charlie and Itchy bump into him with it on the streets the following morning. However, David shows off his new gadget in school, and ends up receiving detention. Charlie, who never had a birthday of his own due to him being a street dog, wants to give David a great birthday. Using David's new voice recorder, Charlie creates an impromptu David look-alike with the voice recorder repeatedly saying mathematical equations and sneaks him out of detention.