Kay and Jay are called in to investigate when a 5,000-year-old Mummy comes to life, ransacks a museum and escapes. They bring with them an unlikely expert in Egyptology...Frank The Pug. The MiB agents and Frank soon determine that the Mummy is actually an ancient alien scout sent by a war-hungry race called the Hyperians. Just as Kay, Jay and Frank are about to thwart the rampaging Hyperian Mummy, Jeebs whisks the alien back to Egypt in his transport pod. Our trio follows, with Frank withholding the fact he and Jeebs are both actually after the powerful "Scepter of Socclarian" used by the Hyperians. While Kay and Jay engage the alien Mummy in an exciting battle in one of the pyramids, Frank and- Jeebs find the "Stargate"-like passageway leading to Hyperia. They pass through and, upon arriving in Hyperia, Frank is mistaken for a living deity and worshipped by the alien race. Eventually, the Mummy also passes through the gateway and Kay and Jay realize that they must seal off the passageway from both sides in order to stop the Hyperians from invading Earth. In the end, Frank is exposed as a fraud by Jeebs while Kay and Jay use the opportunity to escape the Hyperians. Our heroes are barely able to safely pass back through gateway and blow it up behind them, saving the earth in the process.