Peace and tranquility on the island of Aster, home to both humans and 'merfolk', has long been broken by a devastating phenomenon, recurring every five years. A storm including gusting winds and huge waves mysteriously appeared and eradicated much of the population. The misunderstandings, suspicion and hate born of this disaster have torn the two races apart, and the peace loving merfolk are now in a never-ending struggle to prove their innocence and restore peace to the island. On the human side, things are even worse; under the tyranny of cruel king Orestis, the people suffer and all their king cares for is vengeance against the "fish," as he spitefully calls them, executing merfolk after merfolk for just being near his lands. Secrets, intense emotions and strange phenomena will upset their lives forever.

To Reign in Hell chronicles the fifteen years between the Original Series episode 'Space Seed' and the feature film 'The Wrath of Khan' - now widely regarded as a landmark in the Star Trek universe. Defeated by Captain James T. Kirk and exiled with his few remaining followers to the isolation of Ceti Alpha V, Khan Noonien Singh is marooned on a planet that has suddenly transformed into a hostile wasteland, where he and his band of acolytes must fight for their very lives. The once-proud conqueror finds his life irrevocably shattered, and begins his descent into madness…