Continued from ADVENTURE COMICS #452. Aquaman will not let the murder of someone close to him go unavenged, and so he takes the fight to Black Manta, the murderer himself!
The Black Manta has killed Aquaman's infant son. On the hunt for his old enemy, Aquaman is ambushed by the Black Manta's henchmen. As quickly as Aquaman puts one man down, several more appear. Aquaman summons an armada of marine life to even the odds. The Black Manta's men are pierced by sea urchin spines. Their air hoses are cut by sand dollars, thrown by octopi. They are then battered by whales. The Black Manta follows the action on a view screen, within his hidden lair. One of his men, Cal Durham, finds his politics at odds with the Black Manta's methods. Durham is seeking only a place where black men can live in peace and pride. His alliance with the Black Manta was never meant to include murder. Durham attempts to abandon his part in the Black Manta's revenge scheme against Aquaman, but the Black Manta threaten to kill Durham if he tries to leave. Having dealt with the Black Manta's men, Aquaman closes on a barnacle encrusted, World War II era, German submarine. It's hull is emblazoned with the words, "The Conqueror", in fresh paint. Aquaman determines that it is the likely location of the Black Manta. As if to confirm the Sea King's suspicions, Aquaman is attacked by robot manta rays. Aquaman destroys the manta drones easily enough, but falls prey to an enormous robot squid. Held fast in it's mechanical tentacles, Aquaman again summons an armada of marine life to aid him. This time, though, his fish army are intercepted by the Black Manta's robot fish drones. Stalemated, Aquaman finds himself being slowly crushed to death by the robot squid. Meanwhile, in a far away grotto, General Horgan, an officer in the employ of NATO, awakes to find himself the prisoner of the Fisherman. Horgan is not alone, as the Fisherman is also holding several influential statesmen, from countries around the world, in cages. The Fisherman is seeking information regarding the location of a sunken vessel, the Bellerophon. He tricks Horgan into revealing the Bellerophon's location, and makes plans to retrieve it.
Aquaman manages to tangle the robot squid's mechanical tentacles up in knots, effecting his release. With his fish army keeping the rest of the Black Manta's robot drones at bay, Aquaman boards the German submarine. He discovers the Black Manta, waiting for him, on the bridge. As Aquaman rushes to attack his old enemy, the Black Manta electrifies the floor plates, shocking Aquaman into unconsciousness. As the Black Manta moves in for the kill, Cal Durham draws down on his former ally, holding him at gun point. The Black Manta merely snaps his fingers, and several more of his men arrive to subdue Durham. The Black Manta has Durham loaded into one of the submarine's torpedo tubes, then launched into the ocean. Within minutes, Durham, seemingly, drowns. Aquaman is lashed to a large crescent-ended shaft and catapulted into a floating mine field. Still fighting the effects of the massive electric shock he sustained, Aquaman is unable to free himself as he hurtles towards the mines. Before he can hit, a laser blast cuts Aquaman loose, allowing the Sea King to swim away before the explosive impact. Cal Durham has saved his life. Earlier, the Black Manta had subjected Durham to an experimental process, one designed to turn Durham into an amphibian. He survived the drowning attempt, when his gills finally started processing oxygen from the sea water. A brief battle between Aquaman and the Black Manta ends with Aquaman triumphant. Just as he prepares to execute his nemesis, for the murder of his son, the Black Manta cries for mercy. Aquaman finds that he is too noble a hero to act out in vengeance. He spares the Black Manta, turning the villain, and all his followers over to Naval authorities. Durham is among the men Aquaman turns over to the Navy. Upon surfacing, however, Durham finds that he is not truly amphibious, like Aquaman, but can only breath underwater now. A special holding tank filled with water is hastily constructed to hold Durham. Aquaman departs for Atlantis, faced with the uneviable task of telling his wife that their son has died.
Note: The previous issue having been published March 1971, DC relaunched Aquaman with this issue, six-and-a-half years later, as part of the DC Explosion.