Maris is the youngest of her five sisters, one of which was the Little Mermaid, known to her sisters as Aeris. Maris shares Aeris's eagerness to see the Surface, so curious and wondering and always dreaming, hanging on every word of the stories of the Surface she hears from her elder sisters and the other merfolk. But unlike Aeris and her sisters, Maris feels stifled under the waves and wants more than to follow her sisters' examples and rule the Seas.
It is when Aeris leaves the Sea that Maris gains the courage to breach traditions and see the Surface for herself. And what Maris sees awes her -- she sees the land, the people, the humans, and she sees them moving so beautifully. Because her first view is cut short, as she must return home before her family realizes what she has done, she is only more curious, and three days later, she returns to the Surface, swimming closer to land as she watches the people. This continues for days, and then weeks, until Maris's grandmother catches Maris stealing away and Maris is forced to confide in her grandmother her doings. Thankfully, Grandmother understands Maris's wonderment, telling Maris that what Maris has seen is called dancing. Dancing is for humans, who have legs and feet, which dancing requires.
Dancing. Maris whispers the word to herself when alone and tries to mimic the movements of the humans she had seen above. But her fins and tail cannot move like the humans' feet and legs. She is sorely disappointed with this realization, and with each new visit to the Surface, Maris wants more than anything to be able to dance like the humans, with legs and feet. To be like Aeris, who has left the seas to walk upon the Surface -- Maris wants it more than anything.
Her sisters are puzzled when, a year since Aeris left, on Maris's fifteenth birthday, she returns from her first proper visit to the Surface, sullen and unhappy. They continue to wonder over their sister's lack of enthusiasm to what should otherwise be an exciting experience. Maris continues to lay about the rocks and the coastal shelfs, dreaming of dancing for four days since her birthday before she makes the decision to emulate her sister, Aeris, and see the Sea Witch.
Without telling her family, Maris steals away from the merkingdom one last time and ventures to the Sea Witch. The Sea Witch is perturbed by the arrival of the Little Mermaid's sister, but welcomes Maris anyways. She asks Maris what she wants, and Maris responds with her desire to have feet and legs like the humans so she can dance like them. The Sea Witch is surprised by Maris's desire, as Aeris had wanted legs and feet so she could chase love, but she agrees to help Maris, if in exchange Maris gives the Sea Witch her voice, just as Aeris had done before Maris. The Sea Witch explains that while Aeris had the most beautiful voice in the world, Maris has the most beautiful voice in the Sea, and desperate for the Sea Witch's help, Maris agrees.
The Sea Witch gives Maris a potion, not unlike the potion she gave to Aeris, only this potion will give Maris the legs and feet she desires, with no painful effects afterwards -- the Sea Witch is not a heartless creature, and unlike Maris and the rest of the Sea, knows that Aeris has already met her end, and feels great guilt for helping cause the Little Mermaid's tragedy. She gives to Maris the potion, warning that the first drink will be painful, as like Aeris, Maris will feel as if a sword is slicing through her tail, but that afterwards, she will have legs and feet just like Aeris, as well as a soul, and will be able to dance like the humans.
Maris is wary of the warning of pain, but takes the potion with her to the Surface, and along the beaches, she drinks the concoction under the glow of the Surface's moon. The pain is so incredible that Maris loses consciousness and lies bare and cold upon the sands, unknowingly at the shoreline of a great duke's estate. She is found by one of the kitchen servants in the Duke's kitchen, who takes pity on the girl's state and brings her to the Duke's manor. She gives Maris a bed and a decent meal in exchange for Maris working alongside the kitchen staff. But Maris is a horrible servant, missing work constantly so that she can practice dancing, and the kindly woman who took pity on her becomes tired of Maris's antics. She is about to throw the girl out when Maris's dancing catching the attention of the Duke's young, sickly son, Aston.
Aston spends his days confined, considered too weak of constitution to leave the estate, so he spends most his days in the gardens, reading books from his father's great library. As it happens, Maris loves dancing in these same gardens, and one day, Aston sees Maris dancing and is enraptured. He gives Maris her own room complete with beautiful jewels and dresses with even her own handmaids! The only thing the Duke's son wants in exchange is for Maris to dance for him whenever he pleases, as her dancing makes him temporarily forget about his confinement, and Maris, touched that her dancing can make someone so important as the Duke's son so happy, agrees.
Because she can only pantomime in order to convey what she thinks, feels, and wants, Aston teaches Maris literacy. Though Maris struggles with spelling and rather dislikes the lessons, she is soon able to communicate on paper. Aston gifts Maris with a portable wax pad, so that she may communicate the more complicated wants and questions which she is unable to properly convey through pantomime. But despite the gift, Maris persists with her pantomiming, frustrating the manor's staff a great deal and amusing Aston.
He keeps Maris at his side almost always, sharing conversations through pantomime and continuing Maris's literacy lessons with her at his beside. Maris is always ready to leap to her feet to fetch book, handkerchief, bauble, or whatever else Aston desires -- even some cases, she fetches the maids so that they may fetch the local doctor when Aston has one of his violent coughing fits. She listens -- always silently -- when Aston speaks, and tries to create conversations through pantomime before reluctantly turning to her wax pad.
To Maris, Aston is her dearest friend, and she will never stop owing everything to him, and that's all right, because Aston makes her feel appreciated. Unlike her sisters, unlike her father, Aston makes Maris believe that her dancing is important. That it changes people. That everything she's done since -- leaving the sea, making a deal with the sea witch, selling her voice -- was all worth it. And no one but Aston can make Maris feel so special, because Aston was the first person to notice Maris's dancing and not brush them off as the silly dawdlings of a little girl. Of course, this devotion blinds Maris to Aston's feelings for her -- Aston is in love with Maris, but because he doesn't want to ruin their friendship, he says nothing.