It's 1939 in London, and Vivian is being sent out of her home city to escape the bombings. But while she's looking for her Cousin Marty on the train platform, two boys swoop down, abduct her, and ferret her off to their homeland—Time City, a Place Beyond Time from which scholars observe the whole of human history, from the earliest days of mankind to the Depopulation of Earth in Hundred and Seventeen Century. Due to her name—Vivian Smith—they think she's really Faber Vivian, one of the city's founders. And, in fact, one of the people they think is slowly destroying their city! The boys, Jonathan and Sam, quickly realize the error of their ways. One problem—Vivian is from an Unstable Era, and no one is allowed to come out of an Unstable Era, lest the whole of human history be altered!
Now they must pass Vivian off as their cousin, and she must adjust to Time City life. But the city is still falling apart! Will she, Sam, and Jonathan be able to figure out what's causing the city's destruction before it's too late?
Tropes include:
- Artificial Human: Elio. He's called an "Android," but he's not a Ridiculously Human Robot—he's made of flesh and bone, just different.
- Beethoven Was an Alien Spy: Leonardo da Vinci was a megalomaniacal student from the sixty-sixth century, actually. Maybe.
- Big Eater: We really don't know where Sam puts it all.
- Blitz Evacuees: The story begins with Vivian on a train to the countryside to escape bombings in London. Much later, other children from an alternate timeline version of that train end up in Time City as well.
- Cozy Catastrophe: Jonathan's very worried that Time City's days are numbered, but meanwhile the kids continue to go to school, do homework and go on day-trips with their parents.
- Crystal Spires and Togas: Time City is like an Oxford pocket dimension - all fancy buildings and very smart and busy people running around in robes.
- Daddy's Little Villain: Cousin Vivian, in the end, is a loyal accomplice to her parents.
- Don't Eat and Swim: Jonathan and Sam's parents hold them to this during the picnic at the lake.
- Eternal Love: Faber John and the Time Lady.
- Fan of the Past: Elio loves movies, especially older ones like Snow White. This gives Vivian something to bond with him over.
- Fish out of Temporal Water: Vivian, and a lot of the other characters.
- Food Porn: Especially of the butter-pies.
- Future Clothes: the silky coveralls worn in Time City remind Vivian of pyjamas. Jonathan's dad has to wear fancy regalia in his role as Sempitern.
- Hidden Villain: While the story is mainly a race against disaster, the children's attempts to save this city are consistently thwarted by mysterious, time-traveling antagonists who are always a step ahead of them. It turns out the be the Lee family, including the very Cousin Vivian that the heroine Vivian is impersonating.
- Historical In-Joke: Some of the ripples in time caused by the upheaval of Time City are actual historical events, such as the eruption of Pompeii.
- In the Future, Humans Will Be One Race: Sort of. The Lee family seems to be an interesting mix of traits from several different ethnicities; Chinese is the only confirmed one.
- King in the Mountain: Faber John sleeps under Time City. Except it's actually his wife. He himself is very much awake.
- Literal Split Personality: The Casket Guardians are all pieces of Faber John. They re-combine in the end to set Time City to rights again.
- Living Memory: The Time Ghosts are impressions of significant events that play out on a daily basis around Time City.
- Magic from Technology
- Oh, My Gods!: "Great Time!".
- One-Steve Limit: There is quite the abundance of Vivians running around this story. In addition to Vivian the protagonist, she's imitating a Cousin Vivian who appears later—no one seems to care by then, whose father is named Viv (short for guess what). And, of course, the Time Lady's real name is Vivian.
- Place Beyond Time: Time City, naturally.
- Rubber-Band History: The Fixed Eras are explicitly like this—while the Unfixed Eras change and warp, Fixed Eras stay the same so long as not too much gets weird in the Unfixed ones. This all changes when Time City starts its cycle again.
- Samus Is a Girl: The sleeping being beneath Time City turns out not to be Faber John, but his wife, the Time Lady.
- Scavenger World: The Age of Gold, where humanity still keeps certain aspects of technology, but has largely reverted to a pastoral way of life—with lots of raiders.
- Shout-Out:
- Dr. Wilander's name is a shout-out to Wayland the Smith, and thus a hint toward his connection to Faber John.
- Elio, who enjoys movies, at one point starts watching "an animated film about rabbits."
- Sempitern Walker's regalia is reminiscent of the Time Lords' costumes from Doctor Who.
- The Spock: Elio does not have very strong emotions, normally, but he does have a slight sense of humour. And when he realizes he's failed Jonathan, Vivian, and Sam, he comes to understand despair.
- Stern Teacher: Dr. Wilander earned his reputation for being mean. He is consistently rude to Vivian and Jonathan, but they do learn from him. Vivian comes to realize that Dr. Wilander does have respect for her even if he has an odd way of showing it. Dr. Wilander is also notably more indulgent of Jonathan's interest in the Faber John legends than any of the other adults. Which makes sense, considering that he is a 1/4th of Faber John himself, although unaware of it most of the time.
- Stumbled Into the Plot: Amazingly, subverted and played straight at the same time. While Vivian was taken to Time City by Sam and Jonathan due to thinking she is the Time Lady from the Sempitern talking about her, turns out she was who the Sempitern was looking for, because she was leaving a trail of time-destruction in 1939 due to having three versions of her in the same location. Except this whole thing would never have happened if Sam and Jonathan hadn't mistaken her for the Time Lady and taken her to Time City in the first place, making it a Stable Time Loop.
- Time Crash: What the protagonists want to prevent.
- Time Police: The Time Patrol has the job of enacting the timeline-preserving plans that Time City's scientists devise, and keeping the city's observers safe.
- Timey-Wimey Ball: The time-travel almost—but not quite—makes sense if you assume that time is two-dimensional.
- Trademark Favorite Food: Sam loves butter-pie so much, he can eat over a hundred of them in a single sitting!
- You Can't Go Home Again: Vivian's home era being Unstable (i.e., shifting in time) means it's difficult for her to go home. There's also the fact that she's a walking time disrupter. In the end, when history re-settles into new eras, she still can't go home, but Faber John agrees to bring her parents to Time City.
- Zeerust: The oldest portions of Time City bear a slickly futuristic look. The newest portions have gone for a more classical appearance.
