Based on Fujiko Fujio A's manga of the same name.

In the Kagami household, the old Western palm-sized mirror has been passed from from generations to generations. Akko-chan has been taught about the importance of the mirror and when she finally receives it from her mother, she cherishes it with all her might. One day, in the midst of a disturbance made by Taishou and his gang, Akko-chan accidentally broke the mirror. She made a grave and buried the broken pieces in the backyard. That night, Akko-chan was awakened by a flash of light and a kind voice which belongs to the Queen of the Mirror Kingdom. The Queen expresses her gratitude to Akko-chan for valuing the mirror so much and offers her a gift—a magical compact mirror. Whenever Akko-chan sings the magical words, she will transform into anything she wants. (Source: ANN)

Akko-chan is a bright and energetic 5th grader in elementary school whose father is a newscaster and mother is a picture-book writer. Akko always cherishes the palm-sized mirror that was given to her by her father and treats it with care. However, the mirror was accidentally broken by her absent-minded mother. On a night where a beautiful full-moon hangs in the sky, Akko-chan buries the mirror pieces in the garden and goes to sleep. She is awakened by a soft and kind voice which belongs to the Queen of the Mirror Kingdom. She sends her gratitiude to Akko-chan for cherishing the mirror with care and offers her a magical compact mirror. Whenever she sings the magical words, Akko-chan will be able to transform into anything she wants. (Source: ANN)

Transfer student, Aoba Shunsuke, arrived at Sunshine School only to find the premises empty. He was secretly gleeful to be the first to reach the school, oblivious to the fact that it was Foundation Day and a rest day for the institution. At that moment, a big-sized "L"(Eru) beauty by the name of Natsumi appeared before him and the two of them hit off together even though Shunsuke was so much smaller than her. Shunsuke's mother runs a women's apparel busines but the shop is in need of manpower. Shunsuke offers to help out at the shop but fumbles a lot because he does not know how to interact with the ladies. Eru decides to step in and help out around the shop and this pleases Shunsuke's mother. This is a romance story that shares the joys and woes of the "SL" combi between Shunsuke and Eru.