After being accidentally summoned by archaeologist Professor Frith, the mummy of a Mayan baker seeks revenge for the injustice that was done to him thousands of years earlier. Courage manages to hypnotize his owners to be identified respectively as the historical Mayan princess and poohbah for their personal protection. After the mummy feels satisfied of being innocent from his historical accusation, he decides to go home to his tomb in Chichen Itza. Muriel generously gives him a polka-dotted bed sheet as his new entombment, but it originally belonged to Eustace. Eustace pursues the Mayan mummy and cleverly disguises himself as a mummy inside the Mayan baker's tomb. He angrily shouts at him to return the bed sheet. Muriel becomes invisible when she wears a magical gem given to her by Courage, unknowingly. When she is soon captured by the government, Courage and Eustace, with the help of Dr. Vindaloo, set out to rescue her.