Mischievous Kiss the Movie Part 3: Propose.

Kotoko has long dreamed of the day when she is able to be together with Naoki. But when his father’s company faces some difficulties, Naoki agrees to marry the granddaughter of a client’s chairman to save the business. Knowing she should give up on Naoki, she tries going out with Kinnosuke, but even then, all her thoughts drift back to Naoki…