In Sea of Monsters, Hermes asks Percy if he has ever felt abandoned by his parent, Poseidon. Percy says sometimes he feels that way. Hermes goes on to tell him that though they are prohibited from helping directly, nearly all of them intervene in indirect ways...from helpful people coming to their rescue when they most need it, to leaving clues, to sending inspiration at the last moment. Though they might never realize it, all of them work on their children's behalf all of time.
