As a young boy imagines his basement into a wonderful world of make-believe, he discovers that a very real monster lives there. The monster and the boy become best friends as they embark on extraordinary adventures together... until the day the young boy must grow up. Soon, the wonder-filled kingdom they’ve built turns back into an ordinary basement. The monster, not visited for years, grows lonely, and decides to seek out the boy. What he discovers will forever change the boy, the monster, and the world around them… igniting the power of a promise kept.