Let's Open It! The Door to Aikatsu!.Raki Kiseki is about to embark on her idol journey as a second year middle school student. Her dream is to make her own premium rare dress. Raki's older sister is an Aikatsu engineer, who works with the Aikatsu system, and gives Raki a special Aikatsu pass before wishing her luck on her first day. At the idol school Star Harmony Academy, Raki meets Aine Yūki and Mio Minato, who are carrying out the introduction for new idols. Aine and Mio perform in their Jeweling Dresses before the new idols are asked to perform, starting with Raki. After the performance, Raki is talking to Aine and Mio when her Aikatsu pass begins to glow, and a mysterious door appears.