After you talk to the girl after getting the Suzaku Badge, you will need a Agumon Suit. To get it, first talk to the owner of the Azuka Bar. Then, talk to the girl just outside of the bar, Next talk to the grandfather and grandmother near the yellow cruiser. Go to the other way of the secret passage and talk to the boy. Then go back to the main lobby and talk to the same girl again, and again to the secret passage boy. You now have the Agumon Suit.