|In their childhood, the princess Riliane (Rin) and the prince Alexiel (Len) of a kingdom called Lucifenia were playing on the beach. As the sun was setting, they tried to rush home because they might be eaten by a hungry "demon". Alexiel, feeling sorry for the demon since it said that it would be still hungry even if it ate a half of world, offered it his snack. The demon in gratitude told Alexiel, an old legend, a secret about the ocean. Alexiel later told it to his sister.
After King Arth, who built the Lucifenia Kingdom with "Three Heroes", died, Queen Anne (Sweet Ann), ruled over the kingdom. However, a power struggle started among leagues when their twin children Riliane and Alexiel were six years old, and Alexiel was supposed to be dead in the political combat. In fact the Commander of the Royal Guard (and one of the "Three Heroes"), Leonhart Avadonia (Leon) secretly saved him and took him out of the palace, changing Alexiel's name to "Allen". Leonhart raised Allen as his own alongside his adopted daughter, Germaine (Meiko).
This left Riliane, who had grown up in luxury, to rule the kingdom. When she started to rule the kingdom after her mother's death, she imposed heavy taxes on her people and started ruthless purges. Later, Allen returned to the palace as a servant, but Riliane did not remember that he was her twin brother.
A famine started, and Leonhart and lieges who supported him decided to smuggle food from the palace to the hungry. Riliane, noticing a lack of food, ordered her servant to kill the hero. Ney Futapie (Neru Akita), one of the maid of the castle and adopted daughter of Mariam Futapie (Miriam), another of the "Three Heroes", tricked to Allen making him to think that his foster father was going to kill to Riliane. As result of this Leonhart died at the hands of his adopted son. As the hero died, Germaine (clothed in red) intended on revenge. From that day on the princess was referred as the "Daughter of Evil".
Visiting the Kingdom of Elphergot, Allen met Michaela (Miku Hatsune) and Clarith (Haku Yowane), two maids for a wife of a wealthy merchant named Keel Freesis (Kiyoteru Hiyama). Clarith, unlike the other citizens of the kingdom, had white hair. She had lived as an outcast because of this, but by "one-thousand-year tree" she had met Michaela, who had befriended her. Michaela was beloved by many, and had a beautiful singing voice; even the King of the Marlon Kingdom (a prince in the basic plot story), Kyle Marlon (Kaito) was in love with her. She had met him through Keel, who was a friend of the king. Allen also fell in love with her. Riliane, however, was in love with Kyle, and sent a formal marriage proposal to Kyle. Kyle, however, responded that he was already in love with another girl. Realizing this, Riliane told her ministers that if they could not find out which girl Kyle was in love, they should destroy the entire the Elphergot Kingdom and kill all of the green-haired women. Keel hid away Michaela in a well and told Allen where she was. Allen kept it secret from the princess, however the princess found it out later. Allen was passed over a message in a glass bottle from her telling him to kill Michaela. After that, Michaela was killed in the well by Ney Futapie.
Soon after, the rebellion troops and the people of both the Lucifenia Kingdom and the Elphegort Kingdom led by Germaine and a mysterious man with blue hair in a mask named Kachees, who was actually King Kyle in disguise, came to rebel. In response to the rebellion Riliane hired to the Gast Venom and his mercenary group, "The Asmodean Company" but this was futile and the rebels took over the castle. During the revolution Ney managed to get rid of her foster mother while Allen, wanting to protect his sister, offered to switch places with her, allowing her to escape and for him to die in her place. His plan worked, and Riliane was able to escape safely. Before Allen let her escape, he revealed himself as her twin brother.
Riliane went underground during a time and eventually was found unconscious near a cloister by Clarith, who became a nun there recently. Clarith wanted revenge on the "Daughter of Evil", whom she knew had caused the death of her friend. Of course, she was unaware that the girl she found (who knew under the name of "Rin") was actually the "Daughter of Evil" herself, but one day she overheard Riliane's confession in the confession box which revealed to her that she was the princess who ordered the destruction of the Elphegort kingdom. Later, Riliane, filled with regret over the death of her brother, went to the harbor and set a bottled message into the sea. With this, she hoped that it would allow her wish, "If I could be reborn, I would like to be with [him] again", to come true. Clarith, in a blind rage, snuck up on Riliane and tried to stab her with a knife, but decided not to when she was stopped an illusion of a young boy and after see how lonely Rillianne was. Clarith eventually forgave Riliane, and apologized to Michaela for not having been able to avenge her.
Sometime after the previous main events, Yukina Freesis (Yuki Kaai), prodigious child and daughter of Keel Freesis started her own investigation of what happened behind the Story of Evil.