Deep underwater there is a whole world, very similar to ours, where the seas and rivers are kingdoms, and the inhabitants in them are mermaids. Young Serafina is the crown princess of the throne of Miromara, an empire spanning several seas. She will have to undergo an important ceremony, at which she will sing a special spell and prove that she is worthy of the honor bestowed upon her. But the fate of the young mermaid changed forever at the moment when unknown people attacked the palace, seriously wounded the queen - Seraphina’s mother, killed her father, and turned her into a wanderer. Now the princess, hiding from the mercenaries who have flooded the seas, will have to set off on a dangerous voyage in order not only to find out who is behind the tragedy that took place in Miromar, but also to unravel the secret of the ancient prophecy that appeared in her dreams. After all, according to the prophecy, Serafina must find five mermaids with special powers and with their help stop the destruction of the entire underwater world...