On their way to school one morning, Rupert and Bill find some interesting tiles in the forest that perfectly match parts of their outfits. This later leads them to discover a set of buried Roman ruins, which teleport them back in time to Roman Britain, where the ancient predecessor of their village Nutwood is in danger thanks to the insane aspirations of a greedy governor.
This episode provides examples of:
- Arc Words: "One good turn deserves another."
- Be Careful What You Wish For:
- When the boys find the broken remains of the mosaic, the last thing Bill says immediately before they're whisked away to the past is, "It's a shame we can't see what the rest of the picture was like."
- Caesar punishes Governor Porticus for trying to destroy Nutwoodium by demoting him to stable boy.
Rupert: At least he got his wish to return to Rome!Bill: And a post he richly deserves! - Because You Were Nice to Me: Caesar decides to help the boys and Nutwoodium after they and Cedricus help him repair his chariot after it crashes.
- …But He Sounds Handsome: "Caesar would be glad to know you put such faith in his judgment."
- Canis Latinicus: Everyone in Nutwoodium simply has their descendant's name with -icus tacked onto the end.
- Catch and Return: The climax has Rupert and Bill trying to pull a machine in front of the village to deflect a line of stone columns rolling towards it.
- Chekhov's Gun: The mosaic tiles that perfectly match the colors of the boys' clothes.
- Color-Coded Patrician/Purple Is Powerful: The governor and emperor are the only characters who wear purple.
- Down the Rabbit Hole: Bonus points because the boys time travel after literally falling down a hole.
- The Emperor: Caesar (it's never specified which Caesar he is). Claudius Caesar was the emperor who conquered Britain, but Roman rule of the area lasted almost 400 years.
- "Everybody Laughs" Ending
- Exact Words:
- The boys tell Professorius that their home is very far away, "Centuries, you might say."
- Governor Porticus wants a promotion that will allow him to move back to Rome. Professorius assures him, "No one wishes you would be granted a posting back to Rome more than I."
- Expose the Villain, Get His Job: Rupert and Bill are admittedly too young to be governor, but Professorius gets the job after Caesar learns what a tyrant Porticus has been.
- For Want Of A Nail: If Bill hadn't rolled that boulder down the hill, he and Rupert never would have discovered the tiles or ruins, their field trip wouldn't have been ruined, and, depending on which rules of time travel apply, Nutwood and its current residents might not exist.
- Identical Grandson: Every resident of Nutwoodium looks and sounds identical to their descendants.
- Indy Ploy: When Rupert sees the governor is about to have his men flatten Nutwoodium, he says, "We've got to get down there and do something!", drives their chariot down the hill, and has a plan by the time they reach the bottom 6 seconds later.
- Instant Expert: As Rupert tries to insist, he's never driven a chariot, yet he and Bill have no problems controlling it!
- Kill It with Fire: After the kids help Professorius sabotage his machine, Governor Porticus next tries simply burning down the village.
- King Incognito: The two boys help a lone soldier who never does bother to give his name that night…
- Modest Royalty: "Caesar" is depicted as this.
- Never the Selves Shall Meet: The boys never meet their own ancestors.
- Nice Job Breaking It, Hero: Rupert's and Bill's classmates are furious when Dr. Chimp cancels their field trip all because of the artifacts the two found.
- Not Afraid to Die: Rupert and Bill risk their lives trying to save Nutwoodium from being crushed, not moving out of the way even when it looks like they can't stop it.
- Oh, My Gods!: One Roman character says, "By Zeus!"
- Pun: Governor Porticus refers to Caesar's "august presence" (this would refer to his ancestor, who died three emperors before the Roman conquest of Britain).
- The Queen's Latin: All Roman characters are depicted speaking modern English with modern British accents.
- Reasonable Authority Figure: Caesar is given the role of a higher authority with the power to curb and punish the evil authority beneath him (the governor).
- Stable Time Loop: The boys' actions ensure that their future home will exist, allowing them to exist and travel back in time to save the village that will become their home...
- Throwing the Distraction: This is how the kids get the men guarding the machine to leave their posts.
- Time Machine: The mosaic tiles somehow serve as this.
- Would Hurt a Child: When he sees Rupert and Bill in the path of the rolling columns, Governor Porticus simply laughs and has his soldier release the columns.
- Wounded Gazelle Gambit: Ottolinia's role in the machine sabotage plot is to release her horse and thank the centurions for finding him, she thought she'd never see him again!
- Your Princess Is in Another Castle!: The boys initially think they’ve saved Nutwoodium by wrecking Professorius' machine, but Porticus keeps trying one plan after another for destroying it.
