Sunoo is an extraordinarily beautiful merman siren who loves to observe human life. Sunoo often floats in the water watching fishermen and sailors. One day his fish tail accidentally got stuck in the nets. The sailor walked away and did not notice the merman, so Sunoo tried to escape, but he failed.

Then the ship of a dangerous pirate sailed to the shore, whose crew was engaged in trading people and stolen products. This pirate noticed Sunoo and decided to take advantage of his precious find.