Episode 10 - S1.E10

Shumpei tells Keiko to stay with Yutaka, denying liking her. Keiko is convinced he is moving, and spends Christmas eve alone. Later, Shumpei thinks about it some more, and finally realizes that 'Nana' from the phone and Keiko are one and the same. He finds her. "I thought you moved?" "Just next door." Finally, he confesses that it was her he'd loved all along.