The Box Full of Wonders by Karl Newson
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 its not just any box - its 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.