The Camp Half-Blood is protected by Thalia, a daughter of Zeus that sacrificed her life to save the young Annabeth, Grover and Luke from an attack of Cyclops and was transformed by her father into a magical tree. Out of the blue, Percy Jackson (Logan Lerman) is visited by his unknown half- brother Cyclops Tyson (Douglas Smith) and they discover that Thalia was poisoned and is dying. Then the camp is attacked by a Colchis Bull but it is vanquished by Percy. Soon he learns that Luke (Jake Abel) is the one that has poisoned the magical tree.