As either Knights or Vikings, players must use a variety of upgradable projectiles (for the player-controlled ballista), AI units, and spells (as well as their player-controlled hero) to defend their pre-built castle against swarms of invaders while, in most cases, attempting to siege the enemy castle.

The game's campaign, which slowly introduces players to different units, spells, and projectiles, follows the story of Sir Gareth, Protector of the Realm, as he tries to reclaim the Kingdom's Teardrop Gem