Algy can't wait to see what world is waiting for him at the bottom of the garden this time. But when his best friend Cherry shows up with her little brother Brad in tow, he is not impressed. Everyone knows small children just cry and break other people's toys. What use is Brad going to be on an adventure? But in a snowy Arctic world, where monsters lurk and giant footprints lead into the mountains, Algy discovers there might be more to Brad than meets the eye.