Tomokazu is living alone in his house. It is winter, and just as usual, it is cold and everything around is covered with snow. What is unusual is the girl named Saki that he met in the snowy field. The girl claims to be his childhood friend whom he promised to marry once they grow up. He does not have any memory about childhood promise nor he even recall that he has a childhood friend. Yet the girl payed no heed and decided to live together with him in his house on the very same day they met.