Rocky and Bullwinkle must stop the evil Boris and Natasha from robbing a train full of priceless valuables. While Boris uses "Upsidasium" to float the valuables up to Natasha's waiting helicopter, Rocky must fly around and intercept them. When Rocky catches the valuables, he gives them to Bullwinkle for safe keeping. The 2600 version of Rocky & Bullwinkle was actually designed before the Intellivision version, instead of the other way around as was usually the case. Even though Rocky & Bullwinkle was complete and passed quality assurance, it was canceled for unknown reasons. The Intellivision version was still on schedule to be released, but Mattel closed their doors before it could be completed.