Much of the story takes place in the book’s titular location. Percy and Annabeth, accompanied off-and-on by Tyson and Clarisse, brave this monster-infested part of the ocean, for which Riordan draws heavily from Homer’s “Odyssey.” Like Odysseus, the “Odyssey’s” protagonist, the characters in The Sea of Monsters face both internal and external threats along the voyage, and all emerge changed.

To enter the Sea of Monsters, Percy and his friends pass between Scylla and Charybdis, monsters Odysseus faced on his long journey home. Riordan stays true to the descriptions Homer gave the monsters in the “Odyssey.” Charybdis appears as a whirlpool with rows of jagged teeth, and Scylla is an enormous six-headed sea creature. In the “Odyssey,” Odysseus sales closer to Scylla, thinking it best to lose only a few comrades to the heads than his entire ship to the whirlpool. By contrast, Clarisse steers straight for Charybdis, believing she can blast her way past the monster. By not heeding the advice of her fore-travelers, Charybdis’s power nearly destroys the ship and sends it straight into Scylla’s path. The result is the loss of the entire vessel and almost all of those aboard.

In Chapter 13, Percy and Annabeth arrive at C.