Arika lived with just her grandmother, who died when Arika became 15. The grandmother told Arika that her mother was an otome, and gives Arika a necklace from her mother. Wanting to find out more about her mother, and to become an otome like her, Arika walks to Garderobe (a school in Windbloom for training otomes). She meets a girl called Nina Wang, who is from Garderobe.
Arika is from the countryside, so she does not know much about the city of Windbloom. Nina soon becomes angry with Arika's clumsiness. When Arika tells Nina that she also wants to find Garderobe to become an otome, like Nina, Nina does not agree to tell her where Garderobe is, because she thought that Arika was not good enough to be an otome.
They save a girl who is called Mashiro from some men, and Mashiro leads Nina and Arika to Garderobe in return. But they are attacked by a robot called a Slave monster. Nina then makes a temporary contract with Mashiro to protect her, so that she can prove that she was a good otome. Arika finds this very interesting, when the Slave Monster defeats Nina.
They all run to a plane, and Arika's necklace shines, making the plane fly by itself. Nina sees the necklace and thinks that she might be Rena Searrs's daughter. A Five Pillar called Shizuru and an otome called Akane saves them, and leads them to Garderobe. Arika thinks that the otomes are good, and asks the headmaster of Garderobe, Natsuki, that she wants to become an otome as well. Natsuki agrees.
Arika is very cheerful, and seems to be a good potential for an otome, because she is strong. For example, when she saves Mashiro with Nina, she attacks the men with skill. When the nanomachine is put to her so that she can fight with Nina later on, she does not get tired easily. Her power might have come from her mother, Rena Searrs, who was a very strong otome.
But when she sometimes does not understand what is happening, she cries easily, but hides it from the others. She always tries to listen to what her grandmother said before she died. For example, the grandmother once said to her "never to give up hope in a dream," so she does not give up her dream to become an otome.
Meaning of name [change]
Arika in Japanese means a place. Yume in her surname, Yumemiya, means dream. Together, it means that Arika's dream is to become an otome, and she tries to find a place (Garderobe) where she can have her dreams come true.