Pot Sticker Ears (Part Two) - S1.E6

Rio learns that his mother's ears have turned into pot stickers because his older brother Yuu was kidnapped, and Rio feels responsible for what happened. When Rio nearly falls off a cliff while searching for Yuu, Ramune throws himself in harm's way to protect him and ends up badly injured. In order to save Ramune, Rio uses the Pearl of Night Voices he received from Ramune to treat his mother, desperately calling out to his mother, who can't hear his voice.