COLORFUL STAGE! The Movie: A Miku Who Can't Sing

Synopsis (en anglais)

Set in modern day Shibuya, Ichika Hoshino, a high school girl and street musician, encounters an unknown version of Hatsune Miku after hearing a Miku song that she'd never heard before in a CD store. Ichika learns that this version of Miku is having trouble reaching people with her songs, so together they team up to try to touch the hearts of their audience through music. (Source: Crunchyroll News, edited)