Description from the publisher:
 
Castle Panic: Engines of War introduces an engineer who uses new resource cards to build catapults, ballistas, barricades, and more in order to better defend the castle from the growing capabilities of the monsters — and you're going to need his help since they're now charging at you with a siege tower, war wagon, and a battering ram. What's more, they've enlisted the help of a shaman, breathtaker, and goblin saboteurs. Prepare your forces!
 
Castle Panic: Engines of War can be used with the Castle Panic base game on its own or with any combination of other expansions.