"After angering his father Zeus, the god Apollo is cast down from Olympus. He must learn to survive in the modern world until he can somehow find a way to regain Zeus's favor"--
"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"--Provided by publisher.
When Camp Half-Blood, the only safe haven for demigods, comes close to being overrun by mythological monsters, Percy must find his best friend Grover, who is prisoner on an island in the Bermuda Triangle, and then set out to save the Camp.