At the Young Inventors Expo, Penny unveils her latest invention (the Gadgetinis were her entry the previous year) a DNA tracker which can find anyone. Her friend Shawn shows off his invention an invisibility spray and is abducted by MAD Agents since Dr. Claw thinks the sprayer could be useful. While Gadget and the Gadgetinis are stumbling around, Penny finds Shawn but gets herself trapped in the MAD lab. So, the two young geniuses have work together to escape.