Civil unrest arises in the close quarters of Poseidonis, the domed city beneath the ocean. Shalako leads his followers out of the city through the tunnels to sunken Tritonis, where he uses the power of the dark gods to build a hard water dome.
Orin inventst a serum that will turn him into a water-breather. When it works, the whole city takes it. They offer it to the Tritonians, who accept, but are cursed by Shalako for it, growing scales on their legs. They kill him in return.