Stan and Devin thought they had finally succeeded in their mission - Earth has been chosen as the official vacation planet of Pan. The Pants have started coming to Earth for the joyous sensation of sneezing through their nasal processors. But there is a very big problem - they are not allergic to anything on Earth! The only solution is for Stan and Devin to go back in time to ancient Egypt and rescue an allergy-causing goldenrod. Can the heroic duo make the Pants sneeze before it's too late?