Atlantis is under attack by the evil Ocean Master, and it is up to Aqualad, the Mermaid Nicoletta, and their superpets Fluffy the goldfish and Betty the beluga to defeat the supervillain.

Ray Palmer has found a way to shrink himself and his dog Spot to atomic size and become the superhero Atom--so when friend and rival Doris Zeul comes up with a way of increasing her size and becomes Giganta, it is up to Atom and Spot to convince her of the error of her ways.