The daughter of a pirate captain {Sela Voyager}, in order to find the secret treasure "Heart of the Ocean" left behind by her father before his disappearance, she raised a black sail and led the fleet to sea. During the voyage, the fleet was suddenly attacked by a siren. At a critical moment, Sera accidentally discovered that the song of the siren was the key to guiding the secret treasure. She also learned that the Kraken clan is being persecuted by the demons of the deep sea - the demons are trying to seize the heart of the ocean and control the entire ocean. In order to protect the secret treasure and the peace of the ocean, Sera formed an alliance with the Siren. Faced with plunder by other pirate groups and encirclement and suppression by the Imperial Navy, Serra relied on her superb navigation skills and the help of the Kraken to save herself from danger time and time again. In the end, she found the sunken ship, used the Heart of the Ocean to awaken the Guardian God of the Ocean, defeated the demon of the deep sea, and became the "Guardian of Navigation" recognized by all races of the ocean.
