Hanging from a hook on the wall was her New York Yankees cap, her most prized possession from her mom. Once, the cap had had the power to turn its wearer invisible. Since Annabeth’s argument with Athena, the cap had lost its magic. Annabeth wasn’t sure why, but she’d stubbornly brought it along on the quest. Every morning she would try it on, hoping it would work again. So far it had only served as a reminder of her mother’s wrath.

The Mark of Athena, Chapter XVII