This was a fun, fast-paced novel that blended science fiction and historical fiction very well.

Primarily set in 1357 in Castlegard, France, it follows three archaeologists as they travel back in time to retrieve Professor Edward Johnston, the leader of their team, who has gone missing in the middle of the Hundred Years War. They immediately meet with trouble upon their arrival and the action continues from there, consisting of anything from jousting matches to escape plans to a major battle in the War. But trouble continues in the present day as well when the machines that transported the archaeologists are destroyed. The technicians of ITC, the group who discovered how to travel to various historical locations via multiverse travel, have to scramble to repair the damage in less than 37 hours. After that point, the markers that can transport them back will have run out of power.

This book has a lot going for it. There are elements of history, action and adventure, mystery, and, of course, science and technology. While not always edge-of-your seat fast, Crichton keeps up a good pace while also delving into the notions of changing history and creating paradoxes, and how wrong historians can potentially be about actual events, lifestyles, and cultures. I would highly recommend this to anyone who is a fan of science fiction, and even fans of historical fiction who may enjoy some scientific elements as well.