Haruma Kawagoe has always been an only child. Years ago, during a Christmas celebration, his mother miscarried a baby that would have been his sister. That night, a young Haruma knelt and prayed, pleading for his mother’s recovery and for a little sister to be granted to him. As the years went by, Haruma nearly forgot his wish, but Santa hasn’t. One Christmas, when he least expects it, a mysterious present arrives, his long‑desired sister.