Jimmy invents a machine that reduces his brain power; a robotic salesman should win the school's candy-selling contest.

Jimmy constructs the little brother he never had; Jimmy uses his Time Pincher to bring Thomas Edison to the present.

Jimmy gives his Granny a youth tonic; Jimmy goes back in time and gives his parents an investment tip.

Carl is sleep-deprived from a recurring nightmare and thus is too tired to be a useful subject for Jimmy's experiments. So Jimmy invents the DreamInjector 5000 and enters Carl's dream to figure out what his friend is so afraid of. Jimmy and Cindy have to collaborate on a science project.  With the help of Carl, Sheen and Libby, they set off in a submarine in search of a famous shipwreck at the bottom of Retroville Bay and Jimmy's mounting frustration inspires mutiny among the "swabees".

Jimmy accidentally plunges Retroville into a new Ice Age; Jimmy, Carl and Sheen start a band for the school talent contest.

Jimmy adapts his running shoes so that he can move at lightning speed; Jimmy's mind-reading machine accidentally transfers his mind into Cindy's head.