Jason, Piper, and Leo, three students from a school for "bad kids," find themselves at Camp Half-Blood, where they learn that they are demigods and begin a quest to free Hera, who has been imprisoned by Mother Earth herself.

"The Greek and Roman demigods will have to cooperate in order to defeat the giants released by the Earth Mother, Gaea. Then they will have to sail together to the ancient land--Greece itself--to find the Doors of Death"--

"Greek and Roman demigods from the Prophecy of Seven must work together to seal the Doors of Death--and help Percy and Annabeth escape the Underworld in the process"--

Libro tercero de la serie Los héroes del Olimpo
Una lucha milenaria. Siete adolescentes en apuros.
Y el fin del mundo a la vuelta de la esquina.
El destino de la humanidad pende de un hilo: Gea, la madre Tierra, ha abierto de par en par las Puertas de la Muerte para liberar a sus despiadados monstruos. Los únicos que pueden cerrarlas son Percy, Jason, Piper, Hazel, Frank, Leo y Annabeth, el equipo

...

Greek and Roman demigods from the Prophecy of Seven must work together to seal the Doors of Death, and help Percy and Annabeth escape the Underworld in the process.

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...

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.

"THE LIGHTNING THIEF: Zeus's master lightning bolt has been stolen and Percy Jackson is the prime suspect. He and his friends have ten days to find and return it and bring peace to a warring Mount Olympus. To succeed, Percy has come to terms with the father who abandoned him, solve the riddle of the Oracle that warns of betrayal by a friend, and unravel a treachery more powerful than the gods themselves. THE LOST HERO: Jason, Piper, and Leo find themselves...

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.