A seventeen-year-old girl has an abusive father who is obsessed with the ancient Britons, and so she, the dad, and her cowed mother join a two-week college excursion to "live like they did back then" and like, make a fire with sticks and try not to eat anything too poisonous.

That's it. It's very boring. The tension would slowly start to rise, but then it would immediately fall again. The ending was so dumb I thought my copy was missing pages.

Spoiler

The dad ties up his daughter and starts cutting her and she is totally convinced he's going to actually kill her as if she were some kind of ancient bog sacrifice, and even the professor who let them come on the trip is into it, which honestly bothered me more than the crazy dad, but one of the other students gets the police and she gets rescued and then the story just ends, leaving you with no idea what happens to her parents or her.