Tess Burgess, expert in medieval warfare, is building siege engines in France, while running a sting operation against collectors of stolen artifacts. She finds these collectors through her ex-boyfriend, Peter Gagné, heir to an oil fortune.
Obsessed with the collapse of civilization, Peter's latest grandiose scheme is a simulated war, like a giant paintball match for billionaire survivalists, but with crossbows and catapults. He asks Tess if she is good enough to defend an actual castle against medieval siege engines. One of the world's most notorious artifact collectors will be on hand.
Unfortunately, Peter's friends mean to turn the play war into the real thing.