Percy hurries to Camp Half-Blood after his high school is invaded by demonic cheerleaders, and joins his demigod friends on a quest through the Labyrinth, while the war between the Olympians and the evil Titan lord Kronos draws near.

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"--Provided by publisher.

After learning that he is the son of a mortal woman and Poseidon, god of the sea, twelve-year-old Percy is sent to a summer camp for demigods like himself, and joins his new friends on a quest to prevent a war between the gods.

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 1941, fifteen-year-old Lina, her mother, and brother are pulled from their Lithuanian home by Soviet guards and sent to Siberia, where her father is sentenced to death in a prison camp while she fights for her life, vowing to honor her family and the thousands like hers by burying her story in a jar on Lithuanian soil. Based on the author's family, includes a historical note.