The shocking truth is revealed: The tomb of Aquaman’s mother is empty! But there’s something sinister about this development that will change Arthur’s life forever!
Maelstrom, Part 1 of 6
Dr. Shin is requested to return to Triton but instead takes a job from Arthur to along with Daniel Evans, go to Atlantis and figure out why the city isn't recognizing Arthur as it's ruler.
In Atlantis the traitors who attempted to kill Queen Mera are exiled to the Atlantic Ocean where Arthur gives them the means to start a new civilization.
Meanwhile Dr. Shim and Evans use the Touch Stones to reveal that Atlantis doesn't recognize Arthur because it doesn't recognize that Arthur's mother, Atlanna, is dead. When Arthur learns this he swim directly to her tomb, which he finds empty.