Demigod Percy Jackson, still with no memory, and his new friends from Camp Jupiter, Hazel and Frank, go on a quest to free Death, but their bigger task is to unite the Greek and Roman camps so that the Prophecy of Seven can be fulfilled.

At the conclusion of The Mark of Athena, Annabeth and Percy tumble into a pit leading straight to the Underworld. The other five demigods have to put aside their grief and follow Percy's instructions to find the mortal side of the Doors of Death. If they can fight their way through the Gaea's forces, and Percy and Annabeth can survive the House of Hades, then the Seven will be able to seal the Doors both sides and prevent the giants from raising Gaea....

What dangers do runaway demigods Luke and Thalia face on their way to Camp Half-Blood? Are Percy and Annabeth up to the task of rescuing stolen goods from a fire-breathing giant who doesn't take kindly to intruders? Four short stories plus original art, interviews, puzzles, and games, reveal new insights into the world of Percy Jackson and the other heroes of Olympus.

Jason has a problem. He doesn't remember anything before waking up on a school bus holding hands with a girl. Apparently she's his girlfriend Piper, his best friend is a kid named Leo, and they're all students in the Wilderness School, a boarding school for "bad kids." What he did to end up here, Jason has no idea—except that everything seems very wrong. Piper has a secret. Her father has been missing for three days, and her vivid nightmares reveal...

Uniting with Jason, Piper, and Leo after their dangerous quest, Percy, Hazel, and Frank wonder who will be chosen to fulfill the Prophecy of Seven, completing their group's number, and sail with them to an ancient land to find the mysterious Doors of Death.