"The Doom from Dimension Aqua"
Aquaman and Aqualad befriend an exiled Queen of a watery dimension, Mera. Mera has hard water powers allowing her to control water. However, her powers mysteriously disappear after an oil tanker explodes.
Quisp aides them in battling Mera's pursuers.
Aquaman then discovers that oil removes the powers of the beings from the other dimension. Using oil against the invaders he defeats them. Mera reveals that it is actually the lead in the oil that is responsible for the loss of their powers. She then returns to her world.
The first appearance of Mera.