In H. C. Andersen’s Little Mermaid, mermaids are permitted to go to the surface and view nature, humans, and human creations, once they turn fifteen years old. The first part of the story sets up how the youngest longs to go to the surface. She constantly begs her grandmother and older sisters for stories of the surface. Her activities underwater reflect what she thinks the surface will look like, with a garden of flowers as red as the setting sun, and marble statue of a young man that had been lost in a shipwreck.
When it is finally her turn to go the surface, she sees a large sailing ship. As night falls, there is a celebration because it is the prince’s sixteenth birthday. She sees the prince and thinks how handsome he looks. A storm starts that causes the ship to break apart and sink. She remembers how other men that sank had died, and realizes that unless she saves him, the prince will also drown in the water. She finds him struggling in the water, almost out of strength, with his eyes closed. She rescues him, brings him to the water’s surface, and swims with him to the beach. She then hides behind some rocks in the water, and watches him wake up just as a young girl finds him. He smiles very sweetly at the girl that he thought rescued him, and does not know that it was actually the little mermaid.
For quite some time, the mermaid returns to that beach, hoping to see the prince. She finally tells her sisters what had happened, and word gets around to some other mermaids who know of the prince. They tell the little mermaid’s sisters where he lives, in a palace on the sea, and her sisters take her to the palace. She is overjoyed and watches the prince for many nights, while she remains hidden from his view. While spying on him, she hears many tales from other humans of the wondrous and varied places they had visited.
Eventually, the little mermaid asks her grandmother what becomes of humans if they do not drown at sea. Would they live forever? Her grandmother tells her that humans do not live forever; in fact, they live much shorter lives than mermaids, who often lived to 300 years. The grandmother also tells her that unlike mermaids, humans have immortal souls. “Human beings, on the contrary, have a soul which lives forever, lives after the body has been turned to dust. It rises up through the clear, pure air beyond the glittering stars. As we rise out of the water, and behold all the land of the earth, so do they rise to unknown and glorious regions which we shall never see.”
After hearing of the immortal soul of humans, the little mermaid visits a sea witch, who tells her that she can become human. She says that if the mermaid gets the prince to fall in love with her and marry her, then the mermaid, too, can have an immortal soul. The mermaid decides that she really wants an immortal soul, so agrees to the payment that the sea witch demands - her tongue in exchange for a potion to give her human legs. The witch warns the little mermaid that if the man marries another woman, then the mermaid will die at sunrise the next day.
In H .C. Andersen’s story, the little mermaid is mostly interested in seeing the world that humans see and obtaining an immortal soul. Falling in love with and marrying the prince is the means to an end. As can be predicted with these older fairy tales, the prince does marry another – the girl that he thought saved him on the beach when he almost drowned in the shipwreck. On the night that he marries the girl, the sisters of the little mermaid bring her one chance to live. They have a magic knife from the sea witch that will return the little mermaid to the water, if she uses it to kill the prince. The little mermaid sees him sleeping with his bride and decides not to kill him. Instead, she throws the knife away and jumps into the ocean just as the sun is rising.
“She saw the bright sun, and all around her floated hundreds of transparent beautiful beings; … their speech was melodious, but too ethereal to be heard by mortal ears, as they were also unseen by mortal eyes. The little mermaid perceived that she had a body like theirs, and that she continued to rise higher and higher out of the foam.”
She is now among the daughters of the air. They also do not have an immortal soul, but can earn one through 300 years of good deeds.
Quotes are from Hans Christian Andersen's Little Mermaid