Batman: The Brave and the Bold Episode 1.03 Evil Under the Sea!

At a ruined temple, Felix Faust has chained Batman to a column and prepares to open Pandora's Box and unleash the evils within. Faust clamps Batman's mouth shut and prepares the incantation, and a tentacled creature starts to emerge. However, the clamp unclicks apparently by itself and drifts off. Felix Faust throws a magical blast at him but the chains drop free and Batman raises his hand, apparently summoning the book to his hand. Faust tries to blast him but Batman uses the book as a shield and it's destroyed, resealing Pandora's Box. An astonished Faust can't conceive of how the Caped Crusader used such powerful magicks. Batman floats into the air... and the Atom enlarges next to him, having secretly provided an assist. The two heroes knock out the sorcerer.

Batman is flying back across the Atlantic when he notices seismic activity close to Atlantis. He converts the Batplane into a sub and drops into the ocean depths to check it out. As he arrives, Aquaman is having a chronicler document his adventures. Batman notices a figure on a nearby undersea cliff, a sniper who fires a trident. Batman ejects and grabs Aquaman out of the way and the missile destroys the Batplane. Aquaman is glad to see his friend and calls up Fluke, a dolphin who is glad to see Batman: the feeling isn't mutual. Aquaman isn't concerned that someone tried to attack him.

Aquaman's brother Orm arrives and Batman is surprised to see him. Aquaman explains that they are talking for the first time since Aquaman became king of Atlantis. Orm admits he did some foolish things but now he and Aquaman have resolved their differences. As Orm goes to investigate the attack, Batman informs Aquaman about the seismic activity. A seaquake briefly rattles the area and Aquaman insists on going along with Batman to investigate.

Outside of Atlantis, Orm is measuring off the measurements for his new throne room... along with his ally, Black Manta, the assassin. Black Manta assures Orm he will take the throne and he will reap his own reward. When Orm informs Black Manta that Aquaman has left the city, Black Manta suggests that Orm finally step up to become the king.

As they proceed toward the seismic disturbance and Aquaman regales Batman with tales of his many adventures, whales start attacking and none of them obey Aquaman's telepathic commands. A whale swallows Batman and a squid inside attacks him. Batman tries to defend himself but it grabs him. Outside, Aquaman dodges two narwhals and then defends himself with solid-water constructs. They refuse to yield and Aquaman drives them into the seabed by their horns. He discovers two control devices on the creatures and destroys them. The whale attacks him but Aquaman removes its control device and orders it to free Batman. Batman believes that Orm used his own telepathic powers to command the whales and used the devices to override Aquaman's control. Aquaman insists that Orm is innocent and believes that Black Manta is responsible for the high-tech devices. Batman notes that Aquaman feels guilty about the fact Aquaman's mother chose him to rule rather than Orm, and Aquaman tells him to drop it.

They approach the spot of the seismic disturbances but don't find anything. Fluke playfully grabs Batman's seismic scanning device. Aquaman on insists on going back for his coronation party, but as they leave the controlled squid watches from the shadows.

Aquaman addresses his people while Orm sits next to him and secretly places poison in Aquaman's goblet. Batman, watching him, knocks the goblet aside but Aquaman takes the dropper of poison and samples it, noting that sea urchin venom is only a poison to the surface-dwellers. Aquaman order Batman to leave and the guards escort him out. Orm asks for a word in private.

A pair of sharks escort Batman to the coast and they pass the area with the seismic disturbances. Meanwhile, Orm cracks open the windows and the water pours in, and he dons a living costume of fish and announces he is now Ocean Master. The brothers fight and Aquaman knocks him down and asks how Orm could turn against him. Black Manta attacks from the shadows, knocking down Aquaman. Orm activates the control devices he has on the sharks, ordering them to attack Batman. Batman punches one unconscious and uses a batarang to lasso the other and ride it. It scrapes along the bottom and Batman's rebreather is knocked loose. The Caped Crusader retracts the line and gets close enough to tie up the shark's jaws momentarily, but it knocks him toward the ocean floor as both sharks recover and move into the attack.

The villains chain up Aquaman in the dungeon and place a telepathic-nullifier on his head. Aquaman tries to warn Orm against Black Manta's betrayal, and Black Manta immediately stuns Orm unconscious and then chains him up and places a nullifier on him. Black Manta explains that he set up a destabilizer that will collapse the nearby sea mountain on Atlantis, allowing him to plunder the ruins.

Out in the ocean, Fluke comes to Batman's rescue, carrying him to his rebreather. Batman uses an energy net to capture the two sharks and burn out the control devices. In Atlantis, Black Manta projects a holographic image of himself to the people, informing them that their city is to be destroyed. He triggers the seismic device, setting off a seaquake cracking the city's dome. In the dungeons, Orm says it's hopeless but Aquaman whistles and summons several lobsters to free them both. The brothers swim out and agree to set their differences aside for the sake of Atlantis. Aquaman summons an army of sea creatures to attack.

Batman approaches the seismic device but Black Manta is there and informs him he's too late. However, Aquaman and Orm arrive with their aquatic army, but Black Manta has an army of henchmen. As the heroes fight, Black Manta fires an energy blast at Orm but Aquaman gets him out of the way. Batman grabs Black Manta and in their struggle, blows out his wrist blasters, knocking him out. Aquaman and Orm, working together, destroy the seismic device.

Later, Aquaman imprisons Orm rather than exile him, and Batman looks on as Aquaman attempts to teach his brother a lesson by reading his stories to him.