Hyouka - Season 1 Episode 7

The four Classic Club members go on an Onsen trip, which Eru plans. They stay in an inn that belongs to Mayaka's relatives. They are greeted by Mayaki's cousins, Rie (older) and Kayo and their family. Eru mentions that she too wishes for a sibling. After having a dip in the Onsen, Houtarou gets dizzy and is helped back to the inn by Satoshi. Later, everyone (except Houtarou, who is still feeling sick) start telling ghost stories. Rie tells a story about a ghost in the inn they are in. The next morning, during breakfast, Mayaki and Eru claim that they saw the ghost. Houtarou and Eru go about finding the cause, which turn out to be a yukata. While returning from another trip to the onsen, Houtarou explains to Eru that Kayo wore Rie's yukata to the summer festival that day, without anyone knowing, since Rie is pretty conservative about her things. And since the yukata got wet in the rain when Kayo was out, she hung the yukata to dry in the room where the rumored ghost resides, so that the rest of the family would not find out about it. Eru becomes emotional thinking that Rie would not even share her yukata with her own sister, but then, they see Rie carrying a hurt Kayo piggy back, and becomes happy again.