Jack and George are resting quietly when BOOM! A huge and strange ball lands beside them. What's that, Jack? I don't know, George. Maybe it's a rock? No-too soft. But it rolls. Fast! Jack, George and the ball roll right off the cliff and now it's a parachute. But watch out, they're going to land in the river... Jack and George have a brilliant day full of adventure with this object that changes with the landscape. But what is it? It doesn't matter, it was fun trying to figure it out. This bright and funny book is a game of twists and turns, with a joyful refrain and vivid artwork to capture every toddler's imagination.