Doc leaves for Rome to return some ancient library materials, taking Marty with him. Against orders, Jules and Verne tag along, and the four find themselves in an ancient history mess involving one of Biff's ancestors and an escaped slave.
This episode includes examples of the following tropes:
- Aesop Amnesia: Marty forgets the major lesson in common sense he learned in the third movie.
- Big "NO!": Marty screams "No!" when he thinks he sees Doc getting attacked by the lions.
- Chariot Race: Marty, Doc, Jules and Verne went to Ancient Rome, where Marty (as Marticus) had to enter a chariot race against Bifficus (Bifficus called Marty by an Ancient Roman expression translated by Marty's device as "Chicken") and had to lose for sake of space-time continuum because otherwise people would (according to Doc) revolt against Bifficus, which would prevent Caligula from becoming Emperor of Rome. Doc described it as key event to the end of the Roman Empire.
- Chekhov's Gun: Doc's hologram projector shows up early in the episode with Jules and Verne fooling around with it, making it appear that their father is somewhere he isn't. It comes in handy when Doc needs to keep from getting thrown to the lions later in the episode.
- Series Continuity Error: While visiting Rome, Marty accepts a race against Biff's Roman ancestor Bifficus after he calls Marty a chicken. This contradicts the huge lesson about self-control that Marty had learned from his showdown with Mad Dog Tannen in the third film.note
- Shout-Out: When asked his name, the slave Jules and Verne have been running around with answers that he's "Judah Ben-Hur."
- Shown Their Work: The Romans speak actual, genuine Latin (at least until Doc's Translator Microbes kick in), not Canis Latinicus.