Volume 4 - 1st printing. "Underworld!" Collects Aquaman (2016 6th Series) #25-30.

Written by Dan Abnett. Art and cover by Stejpan Sejic.

Enraged by rumors of Arthur's survival in the slums of Atlantis, the ruthless King Rath orders the use of ancient Atlantean techno-magic to track down the Aquaman at all costs! But the ex-king Arthur can't hide for long when his fate collides with that of a mysterious young woman on the run from Rath's own secret police. Her name: Dolphin.

Softcover, 152 pages, full color.