Sykes captured SS Vulcan along with its entire crew, holding them hostage. Aquaman had to perform Syke’s intended misssions in exchange for the continued safety of the captives.
The first task involved entering an undersea cave to obtain a treasure chest. The twist was that the cave unleashed fumes which turned exposed creatures to berserk giants. Aquaman had no way to defeat them. Aqualad then willingly exposed himself to the fumes, growing large and agressive enough to face the enraged sea creatures. Aquaman simply had to wait for the effects of the fumes to expire.
The second task was to acquire a horn-like sea shell. It was located in an island protected by a sea monster. Aquaman managed to enter the island, only to learn the natives were using the shell as their only means of protection against the monster. Aquaman realised the monster was magically bound to the area. He managed to lure it towards the borders of the area, where it immediately vanished.
Aquaman returned to Sykes with the shell, learning the location of the Vulcan in return. Sykes then explained it was the key for controling the magical creature contained in the chest: a “flying genie sea-horse” . Sykes daydreamed of what tasks would the magical sea-horse perform for him. But his attempt to use the shell accomplished nothing. Aquaman had switched the real sea-shell with a fake one. He easily defeated Sykes and his crew. Just in case, Aquaman destroyed the real sea-shell. Ensuring the sea-horse could not be summoned or controlled.
