Description One day, Isaac Thompson is just your average fifth grader playing the part of a porcupine in the school play.
Their search takes them to the Underground, where th.
When Isaac\'s little sister Lily goes missing from their school\'s creepy basement, he and his best friends Max and Emma set out in search of her.
The next, he has strayed into a mysterious subterranean realm that has been lurking beneath his school -- Castle Elementary -- and launches his quest to knighthood.
Description One day, Isaac Thompson is just your average fifth grader playing the part of a porcupine in the school play