This is the animated cover of the Sea of Monsters.
Percy is attacked by Lastrygonians at his school, but is saved by his cyclops half-brother, Tyson and Annabeth. When the three of them go to Camp Half-Blood they notice that Thalia's pine tree (named for the daughter of Zeus, who died to save her friends and whose body turned into a tree upon her death) is poisoned, weakening the borders and allowing monsters to enter the camp. Clarisse, the daughter of Ares, is sent to retrieve the Golden Fleece to heal the tree. Percy and Annabeth decide to go along, but Dioynsus and Tantalus, who replaced Chiron when the centaur was accused of poisoning the tree, forbid them from leaving. That night, Percy sneaks to the beach and meets Hermes, who gives Percy two gifts and some supplies. Percy's friends Annabeth and Tyson find him and they sneak away. On the way, Percy and his friends meet the traitor Luke Castellan. Thanks to Percy's water powers and Tyson's strength they manage to escape from Luke's clutches. They discover Luke's plans to aid the rebirth of Kronos.
Meanwhile, Grover has been captured by the cyclops Polyphemus. Grover creates an empathy link with Percy and calls for help. Percy, through his empathy link, sees that the Golden Fleece is also kept at the island where Grover is being held. Enroute to the island, Percy, Annabeth and Tyson are nearly killed by a hydra, but Clarisse saves them using the ship lent to her by her godly father Ares. However, the ship is destroyed and Tyson and Clarisse are nowhere to be found.
Percy and Annabeth journey to many islands, including the island of the witch Circe and the island of the Sirens. Soon after Percy and Annabeth make it to their destination. They learn they must now save Clarisse and Grover, and take the Golden Fleece. Percy, Annabeth and Clarisse duel with Polyphemsus in vain until Tyson arrives, having been saved from the shipwreck by a hiccopumus named Rainbow. They recapture the Golden Fleece and return to the mortal world, sending Clarisse on a plane with the Fleece so that she can heal Thalia's pine tree. Luke Castellan, under the orders of Kronos, kidnaps Percy again and nearly kills him in a duel, but Percy tricks Luke into revealing that he poisoned the tree by sending the information in a secret Iris message to the wine god Dionysus. This proves Chiron's innocence, and he is rehired at Camp Half-Blood. With the help of the recovered Fleece, the tree is restored to full health and Thalia regains her human form
Meanwhile, Grover has been captured by the cyclops Polyphemus. Grover creates an empathy link with Percy and calls for help. Percy, through his empathy link, sees that the Golden Fleece is also kept at the island where Grover is being held. Enroute to the island, Percy, Annabeth and Tyson are nearly killed by a hydra, but Clarisse saves them using the ship lent to her by her godly father Ares. However, the ship is destroyed and Tyson and Clarisse are nowhere to be found.
Percy and Annabeth journey to many islands, including the island of the witch Circe and the island of the Sirens. Soon after Percy and Annabeth make it to their destination. They learn they must now save Clarisse and Grover, and take the Golden Fleece. Percy, Annabeth and Clarisse duel with Polyphemsus in vain until Tyson arrives, having been saved from the shipwreck by a hiccopumus named Rainbow. They recapture the Golden Fleece and return to the mortal world, sending Clarisse on a plane with the Fleece so that she can heal Thalia's pine tree. Luke Castellan, under the orders of Kronos, kidnaps Percy again and nearly kills him in a duel, but Percy tricks Luke into revealing that he poisoned the tree by sending the information in a secret Iris message to the wine god Dionysus. This proves Chiron's innocence, and he is rehired at Camp Half-Blood. With the help of the recovered Fleece, the tree is restored to full health and Thalia regains her human form