The Lewis and Clark expedition is a bit different than history lessons lead you to believe. In 1804 Lewis and Clark, and their expedition, begin to explore land recently bought from the French. It's while going downriver in their ships when they see the first arch, a huge structure. They are soon attacked by what they first thing are Native Americans but they kill one and, much to their surprise, see it's a Bison Centaur. There's a whole tribe of them. The expedition party takes refuge at a fort, which has only a few survivors-but everyone else there has been contaminated by a weird plant virus, transforming them into zombie-like creatures. It ends with them picking up a few survivors and continuing further into unexplored territory. Volume 1 is a very entertaining book and made me eager to read Volume 2.