One word "plant zombies", or is that two; either way, they were awesome. Some weird plant infecting humans and animals and turning them into undead plant zombies.
Enough about zombies, the story actually follows Lewis and Clark [yeah, the first guys to explore the west, now part as the United States] as they set off by order of the president to explore and catalog all new discoveries and dangers of the west.
Along the way they encounter bison/horse/human monsters and man eating plants with mind control zombie turning powers. Way cool and honestly if history had occurred this way, history in school would have been way more fun.
Rating 5 out of 5