Pyramid Kaoru, a friend from the piano class Ruli that once attended, has gone missing. While searching for her, Hiro is asked a mysterious riddle that he fails to answer and is turned into a golden brick. Kaoru's disappearance is revealed to be the work of the sphinx Digimon AncientSphinxmon, who has been turning people into bricks in order to build a pyramid and revive his master, Pharaohmon. During the fight, Angoramon Digivolves into Diarbbitmon for the first time and unsuccessfully attempts to save AncientSphinxmon from a portal he created.