Jun decides to help Shiena with her studies, which drives Naori crazy. Rumi, on the other hand, seems unusually indifferent about it. However, for Naori, it's clear that she needs to keep an eye on them. So, she quickly invites herself along.

After seeing Mizuma's message, Jun has a decision to make about Rumi. Meanwhile, Naori is plotting something after her chess game, too.