The Golden Yellow Montagne - S1.E6

Karen invites Jun'ichi and his school friends (including their teacher) up to a mountain hotel resort to make up for the events of the cruise ship party. While there everyone continues to hang around and tease Jun'ichi who is not impressed by their company. Karen takes this to mean that Jun'ichi is not satisfied with the luxuries of the hotel and so she takes the group on a long hike up to the Ayanokouji family's secret hot spring. There they learn that the secret hot spring is a co-ed bath, which causes some problems since the there are guys and girls. This is shortly interrupted by the sounds of a beast, and Minato takes off to find out the source of the noise. Jun'ichi, worried for his sister, follows soon afterwards with the rest of the group in tow, only to find Minato bathing in the hot spring with a bear and cub. The bear and cub leave and the group go in for a dip, boys on one side, girls on the other, and Jun'ichi tries to deal with his urge not to peek on the girls. Jun'ichi ultimately gives in, but finds that the girls have already left to interrogate Yuuhi about her relationship with Jun'ichi.