Overworld is a fantasy world, featuring an array of Tolkien-inspired races, such as "primals" or "feys" (elves), "stonebenders" (dwarves), "ogrilloi" (orcs), ogres, and trolls.

The novel is split between the adventure that made Caine a star (Retreat from the Boedecken) and events in the present day.

Both events take place in the same area, and both involve the Ogrillo Black Knife clan who roam the Boedecken Wastes.

The arc was completed in Caine's Law (earlier working title: "His Father's Fist"), released April 2012.

Publishers Weekly gave the novel a somewhat mixed review saying, "Stover has a gift for brutal, detailed action sequences, and Caine is at his most enthralling when he's fighting or discussing tactics, but the high levels of (occasionally creative) profanity and the cliffhanger ending may put off some readers.