Fonz and the gang end up in dinosaur times. Richie and Ralph get kidnapped by cave-people, and Ralph is made king. There is absolutely no reason why King Ralph should be worried.
Fonzie is pulled out of the time machine and materializes in the palace of the evil Ming Fu in Ancient China. Ming Fu finds out about the time machine and seeks it out.
Heading back to Milwaukee 1957 in less than 5 minutes, an unseen vampire materializes on the ship and zaps the controls landing the gang in Transylvania, spookiness ensues.
In 1692, Fonz and the gang end up in Salem for the Witch Trials and are up against both the Judge, falsely accusing witches, but also the Witch of Salem, crashing ships on the rocks.