It's family vacation time, and Johnny is hoping his parents will take them to Hawaii. To his dismay however, they pick Rome, Italy, which he finds boring in the present day. Wanting to see it in its heyday, Johnny asks his sisters to use their time machine to go back to ancient Rome. When they get there, they end up landing right on their ancestor, Testivis, who likewise happens to be the royal meatball cook to the Emperor of Rome, Nero. While Susan and Mary work to get the time machine off Testivis, Johnny and Dukey take his place, shenanigans ensuing.