The secret of the violin! Dancing notes in the wind!

Amu runs home and encounters Ikuto playing his violin. While Ikuto plays, Amu sings until one of the violin's strings breaks. Having no spare string, Ikuto and Amu go to a violin shop for repairs. At the shop, Amu meets Kotone, who has a crush on Ikuto and aspires to be a violin artisan. Another customer stops in and drops off two violins for repair, one of which the customer asks Kotone to repair. Kotone diligently works on the violin. After finishing, Kotone falls asleep, but knocks over a cup and spills tea onto the violin. When she wakes, Kotone notices that the tea has soaked into the violin's frame, panics, and runs off with the violin. When Amu finds Kotone, an X Egg emerges and hatches. Amu transforms with Miki and purifies the X Character. With encouragement from her father and the customer, Kotone continues repairing the violin.