Lena Harper was locked in a seaside cave by jealous classmate Chloe. Swept into the deep sea, she met Lucien Vale, a Merman King sealed for centuries. Their encounter broke his seal. After a night together, Lena fled. Three weeks later, she publicly gave birth to two eggs, from which twins Noah and Luna hatched.
Six years later, the twins began growing scales and fins. To pay for treatment, Lena worked at Vale Estate—only to find her employer was the merman from years ago. Lucien confirmed the twins carried his royal bloodline and grew close to them.
Chloe kidnapped Lena and the children. Lucien publicly revealed his identity as Sea King and claimed the twins as his own. The family of four began living together, and what started as an ancient marriage pact became genuine love.
Lucien’s power grew unstable. Lena discovered she could stabilize the merfolk’s Tidal Mark. Ancient texts revealed she carried the Tidekeeper bloodline, able to balance the Sea King’s power. Meanwhile, hidden enemy Tessa tampered with a paternity test and conspired with Kael Voss, the traitor who had sealed Lucien centuries ago.
Kael launched a rebellion and trapped Lucien in an ancient seal. Lena took the twins undersea and, using Tidekeeper power plus their royal bloodline, awakened the Heart of the Tide and freed Lucien. Together they defeated Kael, ending a centuries-long war for the throne.
