Many prominent citizens are going missing, then turning up robbing stores. When questioned, they only say "I'm dead, Thanatos killed me!"
In the meantime, Aquaman is in the city talking to old friends but is ambushed on the way back to the ocean. He wakes up in a haunted house. When he approaches a mirror, it takes on a life of its own and punches him. He goes through a series of fantasies in which Thanatos tries to kill him.
Meanwhile, the police figure out that Thanatos is a brain-washing method, the evil of the victims is given form in a fantasy, and takes over once it kills them. They break into the building where the brain-washing is taking place at about the same time as Aquaman defeats Thanatos.
This cover is truly striking, with Aquaman being dragged into a mirror by his own reflection. There is a sense of terror there, from the look on Aquaman's face to his hand reaching for a railing.
This story has a genuine mystery to it, and is the first of a lot of fantasy episodes that Aquaman will eventually go through. Thanatos, in this story, is just a brain-washing method. It is later retconned into a villain who causes Aquaman untold torment. You could argue that the underworld thieves masterminding this operation accidently tapped into a greater power than they understood.
Aquaman's fantasies alternate between strange scenerios and home in Atlantis with Mera.
There is a one-page text article by Steve Skeates about how he got into writing comics and how this story came about. It's a good read. There is also a two-page cartoon about Skin Diving.
One of the best Skeates stories.