Happyland has been taken over by the evil Dr. Ronsvolt. The Smilies of Happyland have been turned homiciadal. With the fate of the Earth at steak, you must chase the smilies back to Happyland, infiltrate Ronsvolt's lab and kill Ronsvolt to break his telepathic control over the Smilies.
This was a remixed version of the current tune from labs which had to be cut because it wouldn't save into MIDI properly. Instead, the original from Age of Empires was used.