At school, a group of Laestrygonians attack Percy, but he is saved by his half-brother Tyson (a cyclops disguised as a human). Annabeth takes Percy and Tyson to Camp Half-Blood, but they arrive to find the camp under attack by two bronze Colchis bulls which Clarisse la Rue and Tyson defeat. Thalia's tree has been poisoned, leaving the camp vulnerable to enemy attacks and Chiron is suspected of poisoning it (largely because of his familial connection to the titan Kronos).