December 25th: Goodbye Ume-Sensei - S1.E12

On Christmas Eve, Sae's younger sister Chika comes to visit and gets to meet Yuno, Miyako, and Hiro too. They show Chika around Yuno's school, and they run into Yoshinoya there who later swings by in a Santa outfit and wishes them Merry Christmas. Chika later comes to Yuno's apartment in the middle of the night after Sae refused to give Chika her autograph. Sae, Miyako, and Hiro come by too and they stay up late into the night. On Christmas day, Chika oversleeps and leaves quickly to meet someone in a neighboring town. Yuno and her friends spend the rest of the day together.