The game challenges you to ward off relentless attacks from nasty monsters and to protect the people who sought refuge in your castle. By building various towers, casting magic spells and fortifying your defenses, you can meet monsters' attacks with a barrage of fire, trying to save every villager. Defeating monsters also yields rewards - you get paid for one killed monster and gain monetary bonuses at the end of each attack. You can use this bonus money to upgrade your towers to increase their firepower, fire speed and range.