...
In ancient times, the [Dragon Maiden of the Eastern Sea] commanded the Nightglow Heartshell to trap a giant crab causing chaos in the Eastern Sea, using the sound of the tides as a formation.
Unexpectedly, the crab, with its immense strength, devoured much in the sea and wounded Lady Heartshell when she was setting up the formation, forcing her to retreat to a cave on the island to heal.
...
A boatman, shipwrecked on the island, found the glowing shell. He treated her injuries without fear and refused to leave.
After Lady Heartshell recovered, she asked the boatman his wish. He replied, "I've been away from home for three years. I want to hear my wife's laughter." Lady Heartshell created the [Whisper Across Miles], allowing the couple to connect.
Lady Heartshell also left the [Tide Sound Formation] to trap the crab and returned. The Heart of the Formation lies within the cave, glowing. Approaching, you can see the Spiral Shell Starlight, and hear Spiral Heart Ballad.