Johnny joins forces with Dark Vegan to get him back to his home planet.

Johnny travels to 1845 when school was easier, but he gets stuck there because the power supplier to the Turbo Time Tea house hasn't been invented yet. The sisters and Johnny try to find outdated technology to power the tea house.

After Johnny and Dukey track mud in the house, they use a special stain-remover designed by Susan and Mary, but also learn it can make Johnny invisible.

Johnny, his friends, and his enemies compete with each other in a lawn mower race.

Susan swaps bodies with Johnny so that she and Mary can get a men-only science award.