A band of plundering space aliens dives to the ocean floor, there to harvest sea-life specimens for their own private collection. Among the life forms sucked up by the aliens' demon machine is Aqualad's walrus pal Tusky, who is then miniaturized for easier shipping. In order to rescue Tusky—and by extension everything else beneath the waves—Aqualad and Aquaman must battle a fearsome Venusian sea monster, who fortunately proves susceptible to the "Sea King"'s magic mind games.