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 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"--

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

"Percy is confused. When he awoke after his long sleep, he didn't know much more than his name. His brain-fuzz is lingering, even after the wolf Lupa told him he is a demigod and trained him to fight. Somehow Percy manages to make it to the camp for half-bloods, despite the fact that he had to continually kill monsters that, annoyingly, would not stay dead. But the camp doesn't ring any bells with him." - Amazon.com.