The Sea of Monsters
Percy finds out that Tyson is a Cyclops. Poseidon claims Tyson as his son, making him Percy's half-brother. Annabeth and Percy ask Tantalus to send somebody on to find the Golden Fleece (the wool of a golden-haired sheep in Greek mythology). Tantalus sends Clarisse, the daughter of the god of war, Ares, to get the Fleece. Poseidon gives Percy and his friends three Hippocampi. Together with Annabeth and Tyson, Percy find a cruise ship called the Princess Andromeda. They discover it is owned by Luke. They are captured by Luke in the ship. There, they learn that Luke is trying to reform Kronos. Kronos is an evil Titan lord. They manage to escape from the ship.