"The Greek and Roman demigods must simultaneously prevent the earth mother, Gaea, from waking and stop war from breaking out at Camp Half-Blood"-- Provided by publisher.

"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"--

Caught in the middle of an ancient power struggle, Emily and Pegasus must venture to Diamond Head volcano in Hawaii to track down the one thing that can save Olympus--before the Titans get there first.

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.

"In his penultimate adventure, a devastated but determined Apollo travels to Camp Jupiter, where he must learn what it is to be a hero, or die trying"--

"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."--Volume 1. "Demigod Percy Jackson, and his new friends from Camp Jupiter continue to try to unite the Greek and Roman camps so that the Prophecy of Seven can be fulfilled."--Volume 2.

The Greek god Apollo, cast down to earth as the ungifted human teenager Lester Papadopoulos, and his demigod friends must go through the Labyrinth to find the third emperor--and an Oracle who speaks in word puzzles--somewhere in the American Southwest.