Hiro's parents rearrange the furniture every December. They make space in the corner for something tall. They plug in string lights and leave them on the floor. Sometimes, they cut down a tree but don't know what to do with it. It's not just Hiro's parents. Everyone does it. Come January, they all straighten up their living rooms and everything goes back to normal. They do this every year. No one knows why. Something's missing...