Follows the adventures of a group of neighborhood children who create costumes from cardboard and use their imagination in adventures with knights, robots, and monsters.

"It's nearly Halloween in The Cardboard Kingdom, and one thing is for sure: a mystery is afoot. Nate is positive he saw a monster in his backyard. It wasn't a shadow or a rustling tree. It wasn't his eyes playing a trick on him. It was a monster, plain and simple. But the trouble is, no one believes him. Even his stepbrother, Elijah, says he must have imagined it... Until it shows up over and over again in the kingdom. Always at night, always on the...