Original: Percy receives help from Poseidon, who gives them three Hippocampi, and together with Annabeth and Tyson, ends up on a passing cruise ship, the Princess Andromeda, which is revealed to be owned by Luke.
Simplified: Poseidon gives Percy and his friends three Hippocampi. Together with Annabeth and Tyson, Percy find a cruise ship called the Princess Andromeda.