After reaching the whirlpool that granted access to the Dragon Palace with Orca, Amaterasu and Issun would find themselves at the ocean's bottom. Proceed along the path ahead to come to two guards questioning Amaterasu's authority in accessing the palace of the sea god. After Issun stated the task handed to them by Queen Himiko prior, the Dragon Palace could be entered. Around the entrance are several clam shells containing treasures and items; open all of them.
In the Dragon Palace, move behind the staircase at the entrance to find a cracked wall; blast it open with a Cherry Bomb and jump down the Divine spring hidden behind it to obtain Stray Bead #70. Head back to the entrance and board the elevator on the staircase landing, and Amaterasu would be taken to Queen Otohime's throne room. Listen to her own troubles of the Dragonian people, and accept her request of finding the Dragon Orb. Return to the lower section of the palace by the elevator when Amaterasu has been given the Shell Amulet.
Down at the lower part of the palace, first head to the second floor corridor on the right to enter a room with several chancellors in it; open all the treasure chests there. Then return to the first floor and move down the hallway to the right of the original entrance; at the end of the hallway is a guard, but she would allow Amaterasu access to the room beyond when the Shell Amulet is shown. In the room, use Rejuvenation to restore the destroyed drum at the back, and jump on top of them to access Stray Bead #71 on top of the highest drum. Jump down and use Digging Champ to destroy the rock in the center of the room, blocking the spring there. One of the dancers will then offer to help Amaterasu in restoring the lost spring, and would engage in a digging minigame with her. With it completed, the spring will be restored of its water, but not swirling like what is originally was. Listen to the dancer again, and as the dance troupe runs around the spring, use the Celestial Brush to draw either a circle or a swirl on the water body to obtain the secret Celestial Brush technique Fountain.When Foundtain is obtained, exit the room and move down the corridor on the opposite side of the entrance area. The Water Dragon's garden is beyond the door at the end of that corridor, and once access is obtained, enter the area and open all the clam shells there, one of which contains Stray Bead #72. Then, jump down the gaping mouth of the Water Dragon to proceed with Amaterasu's quest.