Deep in the abyss where the moonlight cannot penetrate, seven siren priests guard the secrets of the mermaid kingdom. The youngest princess, Alison, was born with distinctive scales - light gold fading into deep ocean blue, like ocean waves kissed by moonlight. However, this beauty makes her appear particularly fragile in front of her six powerful sisters.
Above the sea, Princess Serena of the Emerald Kingdom is wearing a silver veil, walking alone in the shadow of the palace. Since the "accident" that took away her parents, her life has become an elaborate game of disguise. Only late at night can she secretly read the logbook left by her parents, looking for clues to the truth.
The tide of fate pushes them towards each other on a stormy night. When Alison revealed her identity to save Serena who fell into the water, the mermaid's scales cut the princess's palm, and an ancient contract across races was concluded. The emerald stars flashing in Serena's pupils and the dancing moonlight on Alison's tail fin intertwined into a symphony of fate in the vortex.
From then on, the fate of the two girls became entangled. Allison must find her voice in the shadow of her six older sisters, while Serena must uncover the truth behind her parents' deaths amid palace intrigue. When the Deep Sea Witch's dark ritual is about to be completed, and when the Duke Regent's ambition for immortality threatens the balance of the two worlds, they must learn to trust each other - even if it means that Alison may lose her singing voice forever, and Selina must give up the kingship at her fingertips.
This is a story about growth, courage and sacrifice. When the sound of the tide meets the crown, when the moonlight interweaves with the emerald, the fate of the two worlds will change due to their choices. Between the waves and intrigues, among the songs and intrigues, they will eventually find their own answers - sometimes, the most powerful power is not dominance, but understanding; the most precious crown is not made of gold, but woven with trust.
Concept: The growth path of two women