Junpei finds a rock and brings it to his tutoring class, where it awakens as Spudio, a messenger from Oedipus. He summons the class to battle Sphinx Paramesos. Mr. Momoya is eaten when they run out of time for the first puzzle, but Junpei solves the second puzzle, remembering the class' earlier lesson about the Doppler effect. Mr. Momoya is rescued, but since he had been eaten once, he loses the thing most precious to him: money from farm trading.