Stronghold is a two-player game telling the story of a siege. Players take opposing sides: one has to defend the stronghold, and the other has to break into the castle as soon as possible. The game board represents the stronghold itself as well as the surrounding terrain, where enemy forces are placed and whence they proceed to the walls.
The defender has a small number of soldiers manning the walls, while the invader has an infinite legion of attacking creatures. A desperate fight takes place every single turn. The invaders build war machines, equip their soldiers, train them, and use black magic rituals to achieve victory. Meanwhile, defenders repair walls, build cannons, train soldiers, and do everything they can to hold the castle as long as possible.
If the invader manages to break into the castle before the end of seven rounds, they win; otherwise the defender wins.