The manhwa is inspired from the Greek mythology, where the Nereids were sea nymphs. In the story, however, Nereids are known as people who are good swimmers, with many of them becoming ocean warriors. The story revolves around a young girl names Matia, who has always wanted to be one of the ocean warriors, and how a false prophecy changed her life, a respected general, a foreign prince, and even several kingdoms.
Learning swimming tactics from the respected Lord Muta himself, Matia is one of the best swimmers among her peers. Matia’s people have a coming of age ceremony when they turn 15 years of age: they have a competition to see who will be to bring the sword of Poseidon back to the shores of Akaron Island, where Matia’s people reside. Kulap, a fellow Nereid, is Matia’s strongest competitor.
At the same time, far from the island of Akaron, the queen of Attica is paying a visit to the Prophet Atropa, who prophesizes that her son, the Prince, her son, will not be the next king. Although he sees the throne covered in blood, he can not see who will be the one usurping the throne. Enrages the queen threatens his whole family, so he randomly names someone, saying taht the one to plunge the country into chaos will be that year’s ocean warrior from Akaron Island, a small province of Attica.
Imeditately upon hearing the prophecy, a group of soldiers, led by General Temedes, heads towards the island of Akaron with orders from the Queen to kill the Ocean Warrior. Although the general finds his orders appalling, he obeys the orders even if it means killing a child. As soon as he is onshore, he takes a walk and encounters an island girl bathing. That girl is Matia. He is memorized by the sight of her splashing playfully around in the water; looking like she’ll become one with the sea at any time. To Temedes, she looks like a sea nymph, a Nereid.
The battle to become the Ocean Warrior is fierce, but Matia wins. But as soon as she steps ashore with the sword raised, the soldiers try to kill her. Matia manages to escape. She soon hears about the false prophesy from her friend Kulap. Angry that she have been wrongly accused, Matia decides to seek out the prophet and clear her name. Matia heads for the capitol, with the sword as her only mean of protection, only after being assure that her mother does alright… unaware that her mother has already died.
When Matia cuts her long wavy hair short, she discovers she is convincing as a boy. So she takes on the name of her best friend, Kulap, whom she beat in the Ocean Warrior race. But the journey to the capital is a difficult one, with coincidences that bring her into general Temedes’s army, where she befriends him.
Not knowing Matia’s true identity, Temedes finds Kulap (Matia) to have great talent and an interesting personality. He is highly amused when she saves and befriends a beautiful wild stallion. The stallion starts following her, and she names him Pegasus.
Unfortunately, Matia discovers there is a huge for whoever catches her, and after a run-in with the foreign Prince Tyon (who attacks Temedes army) she ends up wanted by two sides. The only difference is that Prince Tyons reward of 4000 gold coins will only be awarded if she is brought to him alive. The Prince, not sure whether he wants to kill her or not, is at least certain nobody else should have the pleasure of killing her. The prince also has his eyes on conquering Attica as well.
As Matia starts to grow fond of Temedes, her life gets increasingly more complicated. She is certain that Temedes will kill her if he ever discovers her real identity, and she’ is unaccustomed to life on land. The story goes on with royal intrigues, and innocent lives on the line….