Merry Christmas to All!

On December 25th, Nashiko and her friends decide to hold a Christmas party at the former mahjong parlor. On the day of the party, the table is filled with dishes they've all prepared, and everyone enjoys a special mealtime for just one night. Afterward, when they're full, they take a break and play mahjong. Suddenly, during the game, Nashiko, Pai, and Izumi all smile fearlessly. Seeing this, Tobi suspects Nashiko and her friends of cheating, but...