Aquaman, Aqualad, and Mera are wandering the ocean floor on a treasure hunt, though Aqualad is the only one actually looking. Aquaman loses sight of Mera, then catches up to her and grabs her to give her a kiss. But he figures out that the woman he's holding is not Mera.
And just then Mera rides up and confirms that this woman is Hila, Mera's twin sister and a troublemaker. She was exiled from Mera's world after being accused of a crime committed, along with a guy named Kandor. She claims to have left Kandor, and wants help being good again.
Mera agrees to take her place, and have Aquaman destroy the sorcery that Kandor controls her with. They ride into Kandor's palace... and learn that it was a trap.
Mera learns that it was actually a trap for Aquaman only, and that Hila also double-crossed Kandor. He wants information from Aquaman on how to find the Golden Eels and gain their power. He puts Aquaman through a series of challenges, then enters to battle Aquaman himself.
Back in Atlantis, Hila is passing herself off as Mera, and getting guilty. Especially when the Atlanteans throw her a birthday party. She tearfully tells them the truth.
Kandor challenges Aquaman directly, and scoffs at his nobility. Kandor says he was exiled from his world for a crime he didn't commit. Aquaman offers his help, but Kandor doesn't trust him and the battle starts.
Aquaman is no match for Kandor's hard water powers, and is about to be crushed when a hard water hand reaches out and saves him. It's Hila, and she's come to right her wrongs. Kandor battles the pair while Mera berates herself for being helpless.
But she isn't helpless for long, as Professor Kreon appears in a dimensional gate and returns her powers to her.
Kandor uses his mind control power on Hila again so she won't defy him, and Aquaman, trapped, is faced with two identical sisters: one trying to save him and one trying to kill. Mera defeats Hila, and Kandor rushes to Hila, only to learn that he put Mera under mind control, not Hila, and she wants to kill Aquaman.
The foursome are suddenly faced with Kandor's army of Armadillo Men, in the middle of a revolt. They work together to defeat them, and Kandor decides to free Mera. As Kandor expresses his love of Hila, Aqualad arrives to tell them that they are cleared of the crime and can go home.
This features the first appearance of Mera's twin sister, Hila.
Mera's *sob* reunion with her *choke* sister is a bit silly to read, especially if you are thinking like a comic book fan and expect the double-cross.
The return of Mera's powers happens in this issue, even though she doesn't really begin to use her powers again until issue 24.
If Hila returns home, will she be the queen of that dimension, since she is Mera's twin sister?
Shorts and notable ads in this issue: a one-page cartoon ad for Cheerios starring Rocky and Bullwinkle, and a half-page text piece on "The Color of Water".
Almost pointless plot, but TWO Meras makes up for it.