Ioli is a romantic and sensitive mermaid who lives in her underwater home somewhere in the Ambracian Gulf among squid, lythrins, goslings, seals and other sea creatures. With her lives her little sister Kallirroi, who has a unique desire: to overcome. According to the “law of the bottom” this cannot happen unless the big sister is restored first. But Ioli, despite pleas and connivance, refuses to marry the feudal lord of the seabed whale shark Orca, and the reason is her unattainable love for a man. The poor but honest, orphaned fisherman Constantis. Ioli manages with a magic spell to take off legs normally (instead of a tail) and go ashore. Namely in the picturesque seaside village where Konstantis lives. Along with her comes Kallirroi who whispered that the land is a thorn in premarital relations.