While Nina is fond of Miyake, Kyosuke’s statement of “The one who thinks of us as siblings is her” keeps turning in her mind. Despite promising to spend Christmas Eve together with Miyake, something happens to Kyosuke and…! Is there a more mature development between Nina and Miyake? What about the meaning behind Kyosuke’s surprising statement?! It’s Atsuko Namba’s extremely piercing and pure love story!