Aikatsu on Parade! S01E05 - Lucky☆Halloween

Raki manages to send Hinaki and Juri home to Starlight Academy, but also ends up sending Aine, Mio and herself there too in pursuit of her sister, in order to find out what's happening with Raki's Aikatsu pass. There, they reunite with Hinaki and Juri, and meet their friends Sumire Hikami and Akari Ozora. It turns out that Starlight Academy is hosting a Halloween event with a costume contest, where the two winning idols get to perform as a unit. It also appears that Karen and Mirai have been transported to Starlight Academy and are helping with the contest.