When two families merge and move in together, a little boy finds an escape in his imagination. On the day two families move into a new home to start their life together under one roof, an overwhelmed little boy takes refuge in a simple cardboard box. But it's not just any box—it's a pirate ship, or a castle, or a rocket shooting into outer space . . . the only limit is his imagination. Through creativity and play, the boy learns to share with his new siblings as they create fantastical worlds together.