Content Warning: The source text and this section of the guide include discussions of violence. 

Before Chapter 1 is an Introduction, in which Percy Jackson (the protagonist of the main series) informs readers that he’s writing this collection to help people understand more about the Greek gods. Chapter 1 offers a version of the Greek creation myth, in which Earth forms from the chaos of the universe and develops a personality, known as Gaia. Next, the chaos creates Ouranos (the sky), followed by Pontus (of the water), Tartarus (the darkness at the bottom of the world), and other beings who all come to be known as the primordial gods.

Gaia and Ouranos have 12 children, known as the Titans. Their children put a strain on their relationship, which they try to fix by having more children: first the one-eyed Cyclopes and then beings with hundreds of arms and heads. Ouranos finds them all hideous and imprisons them in Tartarus’s domain so that he doesn’t have to look at them. Enraged, Gaia creates a weapon from Earth’s iron and demands that one of her Titan children kill their father and take his place.