Mei, the youngest sister running Le Concert restaurant on Little Monica's outskirts, exudes youthful charm marked by tearfulness and playful teasing. Yet beneath this playful façade lies a precocious nature and sharp self-awareness about her desires. She deliberately engages her sister Celia's childhood friend, Will, upon his return, adopting an affectation of childish naivete and frequently calling him "onii-chan."

Her musical skill centers on the flute. This talent places her in danger as she participates in covert chamber concerts organized by her sisters, defying the town-wide prohibition on music enforced by the antagonist Kajo. These secret performances carry the constant threat of arrest.

Her background connects directly to the restaurant's operation and the town's cultural decline. Her recurring interactions with Will showcase her intentional blend of playful behavior and underlying maturity.