Astrid Llewelyn's mother is certifiably insane. She raves about killer unicorns at all hours of the day, and seems to think that, if the unicorn population every resurfaces, Astrid is going to go off and kill them. And be great at it.
Astrid just wants to finish high school and go into medical science. Not become a unicorn slayer.
When Astrid finds out that her mother isn't insane and unicorns really are deadly, and that they've returned from supposed-extinction, she is shipped off to Rome where she's to be trained as a real unicorn hunter.
Rampant has an excellantly built world, with wonderfully detailed history of the unicorns and the unicorn hunters. I loved how Diana Peterfreund incorporated myths, Alexander the Great, and nuns into her story, and, for me at least, she made it work.
That said, we'll move on to the characters. In my opinion, none of them had a lot of depth. A few of them seemed like they were supposed to, but it just didn't quite work. Plus, Astrid's life sucks. Everyone sort of tramples over her all the time, and her mother is a... well. I really don't know why Astrid loves her so much. I mean, her mother hurts her, badly.
The one character that was freakin' awesome, was, of course, a unicorn. He had depth, brains, and was edgy enough to be cool but still in a very... unicornish... way.
Along with the history, I also love how the unicorns are the bad guys in this book. They are very dangerous creatures (with fangs) that would kill a man in a heartbeat. There are various forms of unicorns, ranging from little, relatively "gentle" zhis to the giant, dangerous karkadonns (which are even more "extinct" than the rest of the unicorns).
To sum it all up, the writing itself isn't all that spectacular (though the fight scenes, which I have trouble writing, were done very well), but the story was brilliant. In the beginning, you kind of have to make yourself keep reading, but about halfway through it starts to get good enough to where you don't really want to put it down.