Chapter 1: The Aquaman From Atlantis
Aquaman and Aqualad receive an SOS call from Atlantis, sent by Pomoxis. Pomoxis describes a series of explosions that are getting closer to the city, and asks for Aquaman's help. Aquaman and Pomoxis go to investigate that explosions while Aqualad is sent to tell the Atlantean leader that help has arrived.
As Aquaman and Pomoxis approach the mountain belt the explosions are coming from, an explosion occurs. Aqualad sees the explosion and rushes to help them. Aquaman swims out of the murky water and tells Aqualad that Pomoxis is dead, but the danger to Atlantis also seems to be over. They tell the Atlanteans this and leave.
On the surface, Aquaman apparently screws up a rescue, then yells at Aqualad. We are then privy to Aquaman's thoughts, and learn that he's actually Pomoxis in disguise, and that he threw Aquaman into a whirlpool and took his place.
The real Aquaman was catapulted back through time... to ancient Greece.
Chapter 2: The Double Doom
Aquaman runs into a boatload of Persians, who try to kill him, then an island full of Greeks, who are nice to him. He helps the Greeks, who lost their ships in an Earthquake, cross the water to join the defense of the land. Aquaman joins the defense by pretending to be Poseidon and destroying the Persian fleet.
Back in the present, Pomoxis tells Aqualad to patrol alone, then goes to rob ships. Aqualad follows him, and confronts him. Pomoxis captures Aqualad and ties him up and leaves him to die on the surface near an abandoned lighthouse.
In the past, Aquaman notices similar explosions to the one that transported him, and goes to see if he can hitch a ride home. But as the vibrations start, half the mountain starts to fall on him...
Chapter 3: The Battle of the Fish Armies
Pomoxis continues to sink ships and raid their cargo, as Aqualad is nearly dead from exposure. But Aquaman arrives in the nick of time to rescue him. Aquaman explains that he found the time warp and barely made it through. Then Porpy, his favorite mount, led him to Aqualad.
The two go and confront Pomoxis, who engages Aquaman in a battle of fish. Aquaman tricks him with his own Aquaman disguise, and they take him to Atlantis for punishment.
Another interesting Silver Age cover, with Aquaman using fish to catch arrows aimed at him.
The splash page for chapter 2 is split so you see both Aqualad's dilemma and Aquaman's dilemma. This makes the chapter title look even more appropriate.
An obvious question: how does Pomoxis control the fish? Apparently, this early in the run, all Atlanteans had that ability.
Porpy the Porpoise is the first of many Aqua-pets to show up in the solo series.
In addition to the standard ads: a one-page "Facts About Our Oceans" cartoon, a one-page text piece entitled "Secret of the Shark", a half-page "Stan Goes Skin Diving" cartoon, a one-page "Strictly from Hunger!" cartoon (about animal eating habits), and a one-page service announcement cartoon about avoiding fights.
Silly premise (Pomoxis must be really skilled to make a disguise that good) but ok story.