The Lightning Thief is followed by The Sea of Monsters in which Percy and Annabeth rescue Grover who has been imprisoned by Polyphemus, the Cyclopes, and recover the Golden Fleece to save the camp. They are accompanied by Percy's half brother, Tyson and Clarisse in this mission.
Like The Lightning Thief, it won several prizes and received generally positive reviews as well. It sold over 100,000 copies in paperback. It was followed by The Titan's Curse, The Battle of the Labyrinth, and The Last Olympian as well as an entire new sequel-series, The Heroes of Olympus.