During an exhibit of "Really Important Art" at the San Dimas Museum, Bill and Ted think they have dis-armed the Venus de Milo and journey back in time to get it repaired.
To prevent Missy from singing the Star Spangled Banner in public, Bill and Ted travel back to the War of 1812 in order to convince Frances Scott Key to write a song that is easier to sing.
Ted's dad is threatening to send Ted to military school, so the dudes visit him as a teenager to learn discipline, only the find Ted's dad wasn't as disciplined as he claimed.