The planet Emoria is being destroyed by a plague, and a Corsair in the Sky Lord's Navy has been tasked with finding out why and stopping it. Sky Cannoneer is a tower-defense strategy game in which the player builds and upgrades a Battle Haven—a flying fortress equipped with forts, augmentations, and a selection of technologies, superpowers, and summons chosen before each engagement. A story campaign with dozens of scenarios and multiple boss encounters runs alongside the strategic layer.