Percy finds out that Tyson is a Cyclops and thus also a son of Poseidon. The campers begin to mock Percy's relationship to Tyson, causing him to be greatly embarrassed for having the latter as a brother. Meanwhile, Tantalus revives an ancient tradition in the form of a chariot race. Percy and Annabeth have a fall-out, partly because of their quarrel about Tyson joining their team, and partly because of her strong dislike for all Cyclopes in general. During the first competition, the campers are attacked by Stymphalian Birds. Although Percy, Annabeth, and Tyson help stop the attack, Tantalus accuses them of disturbing the birds with their "terrible driving.