On the hunt for the missing cargo ship Vulcan, Aquaman and Aqualad instead encounter one Captain Sykes, and his ship, the S.S. Seahawk. Captain Sykes wastes no time in boasting that it is he who has spirited away the Vulcan, and her crew. Using the hostages as leverage, Captain Sykes forces Aquaman to retrieve two ancient relics, for his "maritime collection." Following a map provided by Captain Sykes, Aquaman and Aqualad locate the resting place of the first relic, dead center in an enormous coral mountain. Issuing out a telepathic command, Aquaman instructs hatchet fish & swordfish to begin chipping away at the coral, while a host of other fish carry away the debris. Finally, Aquaman commands a porcupine fish to break through the remaining thin layer of coral separating them from the artifact. Upon breaking through the final barrier, an unknown gas is released into the chamber. The effects of the gas are twofold. Three of the fish... the porcupine fish, a cow fish and a goosefish... all grow to gargantuan proportions, while becoming increasingly agitated. Aquaman and Aqualad attempt to flee the chamber, but the goosefish blocks the egress. Surrounded, Aqualad desperately swims into their midst, to drive them off before they reach Aquaman. Exposed to the gas, Aqualad, too, expands to giant size. Aqualad makes quick work of the enormous fish, before turning on Aquaman. Before Aqualad can attack his mentor, the last of the gas seeps from the chamber. No longer under the influence of the gas, Aqualad returns to normal size and sanity. With the danger passed, Aquaman retrieves the relic from the broken coral cavern. It is a small chest, with no visible opening. Aquaman returns to the S.S. Seahawk, and turns the chest over to Captain Sykes. Aquaman is given another map, with the location of the second artifact marked upon it. This time, their destination is Pecos Island. As Aquaman and Aqualad draw near to Pecos Island's coast, a great sea serpent surfaces from beneath the waves, driving the heroes away.
Making for open sea, Aquaman and Aquald are only barely able to stay ahead of the creature. It rears up through the waves, as if to pounce on the two heroes, when suddenly, it falls back, unwilling to pursue them past a certain point. Keeping Aquaman and Aqualad level with it's eye line, the sea serpent waits. Never venturing any farther forward. Aquaman notices that the creature ignores a school of passing fish, and thus summons hundreds of fish, instructing them to form a tunnel to the shore. Aquaman and Aqualad are able to swim to Pecos Island unseen by the sea serpent, but as they break the surface & rush the beach, the creature turns & comes for them. As the pair escape into the jungle, the creature rampages through the docks and boats lining the shore. In the jungle, Aquaman and Aqualad are suddenly surrounded by the native islanders, who take the duo prisoner, at spear point. Aquaman petitions the tribal leader for their release, stating that they have only come to Pecos Island to retrieve the second relic, a wailing shell. Outraged, the tribal leader informs Aquaman that the shell was created by a powerful wizard. The wailing sound emanating from it keeps it's protector, the sea serpent, at bay. As long as they have it in their possession, the creature will not venture any further inland. Aquaman offers to remove the sea serpent as a threat, once and for all, in exchange for the shell. Scoffing, the tribal leader releases Aquaman, while continuing to hold Aqualad hostage. Aquaman returns to the sea, where he is immediately set upon by the sea serpent. Telepathically summoning dozens of electric eels, Aquaman instructs them to prod the creature with a massive electrical charge, distracting the sea serpent long enough for Aquaman to swim past it, rapidly heading for the open sea. The creature gives pursuit, but once again stops short of leaving the island's coastal waters. Aquaman again instructs the electric eels to strike. As the sea serpent lurches forward to escape the stinging shock, it crosses over the coastal water boundary, and fades away. Aquaman has correctly surmised that the wizard that created the sea serpent, rooted it to Pecos Island. Provoking it to move out of the island's coastal waters broke the spell, causing the creature to vanish. No longer prisoners of their own home, the grateful islanders reward Aquaman with the wailing shell.
Returning once again to the S.S. Seahawk, Aquaman, this time, refuses to give up the relic, until Captain Sykes releases the Vulcan hostages. Captain Sykes relents, leading Aquaman and Aqualad through a hidden pass through the cliffs lining the coast line. There, a secret bay opens up before them. The crew of the Vulcan are allowed to get their ship back under way. It is only after the Vulcan has been given safe passage, sailing across the bay, through the hidden pass, & into open water, that Aquaman passes the wailing shell off to Captain Sykes. Cackling in triumph, Captain Sykes gleefully tells Aquaman that the sound vibrations of the wailing shell will open the chest, releasing an indestructible, immense, aquatic genie-like creature, that will be his to command. With it by his side, Captain Sykes will plunder all cargo ships and sink all naval vessels that oppose him. Of course, he'll do away with Aquaman and Aqualad, too. Captain Sykes holds the wailing shell against the chest, but nothing happens. Aquaman has substituted a clever lookalike for the real wailing shell. Captain Sykes is thwarted. In a rage, Captain Sykes orders the pirate crew of the S.S. Seahawk to kill the two heroes. Aquaman and Aqualad dive for the bay. Octopi disarm several of the pirates, while a swordfish relieves another of his pistol. Captain Sykes pulls a lever that lowers a massive gate across the entryway to the bay, trapping Aquaman and Aqualad with the villains. As Captain Sykes brings up a machine gun to finish the heroic pair, Aquaman commands a nearby sperm whale to bring him an anchor chain, which he quickly ties to the gate. The sperm whale then tears the gate loose from the cliff walls, with such force that they begin to collapse. Aquaman orders Captain Sykes to lay down his arms, or he'll leave him to die in the rapidly collapsing cavern. Captain Sykes quickly complies. He and his pirates ride out atop the sperm whale,watching, as his secret maritime base is buried in tons of rock and debris, Captain Sykes is turned over to the authorities. Unable to destroy the impregnable chest, Aquaman settles for having a hammerhead shark shatter the wailing shell. Without a key, the chest, with it's terrible contents, will remain sealed forever.