After escaping the destroyed bus in the rain, Percy, Annabeth, and Grover stumble through the New Jersey woods with no money, food, or clear route west. Percy and Annabeth argue about his reckless rescue during the Fury attack, then briefly reconnect when Annabeth admits how much this quest matters to her because it is her first real chance to test herself outside Camp Half-Blood.

The trio follows the smell of food to Aunty Em's Garden Gnome Emporium, a strange roadside statue warehouse. Grover senses a monster and is disturbed by the lifelike statues, but Percy and Annabeth are too hungry to resist. Inside, the veiled owner, Aunty Em, welcomes them, somehow knows Annabeth's name, and feeds them cheeseburgers and shakes while talking sadly about her ruined life and her two sisters.

Annabeth grows suspicious and tries to leave, but Percy, still lulled by food and Aunty Em's voice, agrees when the woman asks them to pose for a photograph among the statues. Outside, Aunty Em reveals herself as Medusa. Annabeth turns invisible and warns Percy not to look up, Grover attacks blindly from the air with his flying shoes and a tree branch, and Annabeth gives Percy a glass gazing ball so he can fight by Medusa's reflection instead of her deadly gaze.

Using the reflection as a guide, Percy beheads Medusa with Riptide. Back inside the warehouse, Annabeth explains Medusa's grudge against Athena and her connection to Poseidon, which leaves Percy angry at the gods and at being dragged deeper into their conflicts. Searching Medusa's office, Percy finds shipping records showing that statues have been sent to the Underworld and that an address in West Hollywood is linked to it. Still furious, Percy packs Medusa's head and sends it by Hermes Overnight Express to Olympus, openly defying the gods before the group prepares to make a new plan.