Meet two friends who think they're building imaginative worlds with blocks but come to realize they've been building something far greater--a sturdy, solid friendship--in this picturebook by award-winning creators. Two kids build entire worlds out of blocks, cardboard, and imagination. From boats attacked by a sea creature to a castle crumbling into the ocean. And they don't mind when these creations break apart and CRASH to the floor. In fact, they think it's pretty funny! Every time, a creation falls apart, they pick up the pieces and keep building bigger and better. But when their latest masterpiece tumbles down in spectacular fashion, the boys aren't laughing anymore. Have these two friends reached their breaking point? Playful text by wordsmith Minh Le and dazzling illustrations by artisan Dan Santat showcase their close collaboration in their latest picturebook. As merry as it is moving, here is a story that recognizes the friendships in life that are truly built to last.