A nuclear submarine is attacked in the Atlantic Ocean by Atlanteans, forcing the League to come face-to-face with Aquaman. Aquaman takes Superman up on his advice to go to Metropolis and take his problems up with the various governments of the world. When a mercenary, Deadshot, attacks Aquaman, the League steps in. Aquaman discovers that Lord Orm, his own brother, was behind the attack and is attempting to usurp control of Atlantis and wage war on the surface.
- Arc Villain: Lord Orm, who falls to his presumed death at the end of the story, never to be seen or mentioned again. The writers later admitted that this was done just in case they wanted to bring him back for another story, plans which never materialised (possibly in part because in later seasons, Aquaman was Exiled from Continuity, making any such idea unworkable).
- Cain and Abel: Aquaman and Orm.
- Captain Obvious: When Superman asks Deadshot why he tried to kill Aquaman, he sarcastically asks, "Gee, why would a hired gun try to shoot somebody? Could it be that someone paid me to?"
- Disney Villain Death: The impact of Orms death via a deep fall is not shown.
- Everyone Calls Him "Barkeep": Nobody who uses Aquaman's name refers to him by his real name (Orin, in his case).
- Gory Discretion Shot: We see Aquaman swinging his sharp belt buckle, and find out what he was doing when he returns with the baby's blanket wrapped around his severed wrist.
- Just Following Orders: After Orm's defeat, the soldiers that defected are brought to the throne room. General Brak appeals to him using this line. Aquaman is not impressed. It's worth noting here that Aquaman was still the rightful king and they did violate their oaths of service to the king by following a usurper, so no, the justification does not hold up.Aquaman: Get them out of my sight.
- Life-or-Limb Decision: Aquaman had to cut off his hand to free himself and save his son. Just like in the comics, he gets a Hook Hand.
- Mass "Oh, Crap!": When Aquaman tells the Justice League of the Doomsday Reactor, everyone in the room has their jaws on the floor from shock.
- Papa Wolf: Orm's attempt on his nephew's life voids any affection Aquaman might still have had for him.
- Prongs of Poseidon: Aquaman, as always.
- Reality Ensues: Why General Brak's defense of Just Following Orders does not hold up here. He and his soldiers violated a direct order from the rightful king, Aquaman, and followed the orders of an illegitimate monarch, so their actions constitute high treason.
- Save the Villain / Take My Hand: Subverted. Orm ends up dangling off a ledge over a high drop, screaming for help, after trying to kill both his brother Aquaman and his infant son as well as untold numbers of people by melting the polar ice caps. Aquaman reaches down... and grabs his nearby trident instead, while Orm falls to his death.Aquaman: I believe this is mine.
- Tempting Fate: After he gets captured, Deadshot blusters "You can't scare me, Batman." After a quick "word of advice", he's telling all he knows.
- Wounded Gazelle Gambit: Implied that Orm tried to do this when begging Aquaman to save him from falling. When Aquaman reached down, Orm was seen smirking, but then loses all color in his face when Aquaman was simply picking up his trident, leaving him to fall to his death.
- You Do NOT Want to Know: Superman refuses to tell Wonder Woman what Batman said to scare Deadshot. His expression suggests that he wishes he hadn't heard it himself.note
- You Don't Look Like You: Aquaman is given a completely different look here and for the rest of the DCAU from how he looked back in the Superman: The Animated Series episode "A Fish Story" and his brief cameo in the Batman Beyond episode "The Call".
- The redesign followed the new look Peter David gave him in his comic book but omitted how David showed his look changing.