Premise
Elias, a fisherman, falls in love with and marries Esther; spurning the love of Victoria, a witch. Heartbroken, the vengeful Victoria places a curse on Esther and Elias's unborn child. In the hopes that Victoria will lift the curse on his child, Elias abandons Esther for Victoria and they have a child of their own, Luna. Meanwhile, Esther raises her and Elias's daughter, Cristina, on her own. On Cristina's seventh birthday, Victoria's curse comes to fruition and Cristina is transformed into a mermaid. Elias assaults Victoria in retaliation and cripples her. He is then attacked by Dugong, a sea-witch and Victoria's cousin, and loses his sanity. To save Cristina from the superstitious fishermen, who believe mermaids to be unlucky, Esther is forced to release her daughter into the sea. There, she is taken in by the other mermaids and adopted by their queen Istah, and renamed "Marina."
Though happy among the mermaids, Marina dreams of being able to walk again and reclaiming her human life. Istah gives Marina her precious necklace as payment for Dugong, who is able to restore Marina's legs.
Marina becomes human again and returns to the land to reclaim everything. However, she soon discovers that she becomes a mermaid again during the full moon, only true love's first kiss can break the curse. Dugong, on the other hand, learned that the powerful necklace of Istah was a trap. Donning the necklace, she discovered that she cannot remove it, and worse, suffers the same injuries Marina does.
Meanwhile, Dugong's mother and Victoria's aunt, Tandang Ella, pays a visit to Victoria. She trades the power of the Aram for a chance to see her daughter again. Dugong, having been separated from her mother since she was an egg, harbored ill feelings but, upon learning that her mother is alive and is looking for her, could not help looking forward to meeting her mother. Victoria, however, tricks the old woman and kills her the moment she met her daughter, believing Dugong hated her mother anyway. She kept the power of the Aram for herself.
On the eve of Marina's 21st birthday, Victoria and her daughter Luna pay a surprise visit to give her stepdaughter her "gift". Using the powers of the Aram, she turns Marina back into a mermaid. Victoria then went to a circus where she made the poor mermaid the star attraction. When the circus master wanted more oddities to star in the circus, Victoria also used the powers of the Aram to capture Dugong and her slave, Pearly.
Rodge attempted to rescue her love but Luna had placed him under a curse, turning him into a cat, while Victoria used the powers of the aram to turn Marina into a fish. Eventually, with the help of her newfound friends, Marina was able to get away from Victoria's clutches and eventually found her way into another fishing town, to a family of fairies.
The King of the Seas ordered to have Victoria and Luna arrested and placed inside a force field prison to prevent them from escaping. Marina, on the other hand was now able to live her life as a human when she married Rodge and was now pregnant.
All things seem well except for Victoria. She wants to get revenge on the people who foiled her evil plans. She had heard of a meteorite stone that, once in the hands of its owner, can give out an enormous power. She escaped from her prison and got her hands on one of the stones that fell that night. By using its power, the evil witch had Luna and Marina switch places, with the latter's unborn child now in Luna's womb.
One day, Marina woke up, found herself inside a prison and the shokoy guards calling her "Luna". She eventually came to the conclusion that Victoria will not rest unless she gets her way. Asking help from Dugong's sister, Ignarva. Marina turned into a mermaid again as an exchange of Ignarva's assistance, hoping to claim everything Luna took away from her. With the help of many of her friends who see her as Marina beyond what they physically see, they were able to break Victoria's spell, although Marina's child was still inside Luna's womb (in a later episode, Luna gave birth to Marina and Rodge's baby girl who was later named Mariluna and seems to be inheriting Marina's curse).
Victoria still won't give up, that's why she had Marina killed but at the cost of her life. Marina's mother Esther began having dreams in which Marina is talking to her to get the Leafar, a magical liquid that can resurrect the dead. But Victoria was able to get into the gate connecting the world of the afterlife and the world of the living, with Marina standing in-between. Esther was surprised to see that whom she had resurrected was not her daughter but the ever-evil witch.
Marina, lost in-between the two worlds, gets help from her father, who is now a spirit. The only way to revive herself again to finally defeat Victoria is to return herself into a mermaid once more.
Eventually, she is able to defeat Victoria but at the cost of it, her last chance of being human forever. She gave her child under the care of Luna and told her to take care of her child as well as her husband, Rodge. Marina, now a mermaid for eternity, bid goodbye to Rodge and their child and returned once more into the ocean.
