S1·E10 Brother Invasion

Mutsumi finds a hidden treasure map in the History Club room and invites everyone to go treasure hunting. Igarashi, Nanashima, Shinomiya and Nishina are less than thrilled about the idea, but after finding out Kae would be going alone with Mutsumi, they decide to go too. The four of them are confused by Mutsumi, because he treats Kae now the same way he always had. And so, they decide to ask him how he really feels.