In High Places is the third installment in Harry Turtledove's Crosstime Traffic series. This series seems to be aimed at teenagers, and each book is written as a stand-alone work. New characters and storylines exist for each novel.

What they have in common is the concept of Crosstime Traffic. Crosstime Traffic is a company in one universe that has figured out how to jump to parallel universes at the same point in time. Each universe split from its neighbor at some instance in the past. Thus, there are worlds where the human population never advanced very far, just as there are worlds where humans advanced to a point that they had the capability to destroy themselves -- and they did. Whatever you can imagine, you can conceive of a universe where that idea is reality. In short, Turtledove uses the concept of Crosstime to rewrite history in any way he can dream up.

In High Places focuses mainly on Annette Klein. It is the summer before her first year in college. As she has done for every summer since she can remember, she has joined her mother and father on a trip to a universe where the Black Plague of Europe was far worse than in what she terms the "home timeline." Four out of every five Europeans were killed. Consequently, the Muslims made it much further into Europe than they did in our reality. Technology never progressed much further than what we would term the Middle Ages. Kingdoms and principalities are the order of the day, not countries, much less a European Union. Annette and her family go to Versailles posing as wealthy Moorish traders. In this much poorer universe, Annette goes by the name of Khadija.

Jacques is a young soldier in the Kingdom of Versailles. He prays to Henri, God's second son after Jesus. (In this universe, when the Black Plague struck as hard as it did, God sent his second son to provide hope for the populous. The current king of France and pope did not believe Henri was the son of God, but the day after breaking him on the wheel, God brought a church down on both men as they were thanking God for deliverance from this deceiver. You might say it could have been an earthquake or shoddy building practices, but that obviously proves you have little faith.)

You probably have several questions, such as why trade with these poorer universes at all? Well, the home timeline needs these links of commerce to provide for its own people. Not to mention there are products in various universes that are unique to those universes, or at least rare in the home timeline. That may be, you might say, but why not just take what you want by force? That wouldn't be right. People need to be treated with respect regardless of their race, religion, sex or universe of origin. This is also a great opportunity to study the causes for why one universe went in a different direction than another. Besides, Crosstime Traffic has a policy of keeping itself a secret in all these parallel universes. No need for the locals to figure out the secrets of Crosstime. Everybody believes that!

Or so Annette thought. She and her family are heading back home, but have to travel with a caravan to get to where the Crosstime Traffic chamber is hidden in this universe. Jacques is one of the soldiers ordered to help guard the caravan on its journey. He has also been ordered to spy on Annette's family. There is something strange about them. Their French is a little too perfect (thanks to implants from the home timeline). They make light of some Muslim practices more than a true Muslim would. They seem very wealthy for sellers of olive oil. They are just a little too smart and act as if they know something. But all the guarding and spying are for naught when the caravan is raided and the prisoners taken to be sold into slavery. Whereas Jacques takes slavery in stride -- God must have a plan for him -- Annette is outraged. But it is even worse than that. Annette ultimately figures out the slavers are from her own timeline! How can that be when Crosstime Traffic has all these rules and regulations in place?

The bulk of the book focuses on the lives of the slaves and Annette's need to escape so she can get back to the home timeline and let authorities know what's going on. Over time, her relationship with Jacques changes as she reveals the secrets of her identity in the only friend she has in this universe. If you are curious to know if and how Annette escapes back to her home timeline and to see if anything is done against these renegades, you will have to pick up your own copy of In High Places.

Turtledove has a Ph.D. in history and has been writing novels about fictitious history for years. His writing style is rather simple to follow, although he has a habit of repeating himself a lot. For example, Annette might ponder just how wrong slavery is and will practically have a little speech arguing against it in her head. A chapter or two later, a variation of those thoughts will be spouted again. Despite that, In High Places is the better of the two Crosstime Traffic novels I've read. In fact, if time wasn't such a premium, I probably would have read this book in one sitting. At less than 300 pages with such an easy writing style, it would only take a couple hours.