Marisko's father's ship disappears into the sea. Has he really fallen into the black abyss of the Sea Devil? The evil Zhadun takes away the house, and Marisko and his mother settle in a dilapidated house on the seashore. Marisko saves the kitten Katie, who becomes his friend, and from that moment his life turns into a series of exciting, sometimes very dangerous adventures. A bloody pirate kidnaps his beloved girl Tora and sells him to the invincible Devil. Marisko and Katie, rushing to her aid, go to the witchcraft the Devil's lair and find themselves at the ceremony of transforming the Torah into... Will they be able to save the girl? Where does the power of the Sea Devil lie?