Downside up

"Fred Berdit is a sixth-grader reeling from the loss of his beloved dog, Casey. Every day he walks home from school bouncing Casey's old worn out tennis ball. When the ball falls through a sewer grate, Fred goes after it, ending up--or is it ending down?--in another world. At first the place looks like home--same park, same sewer, same house, same family. But in this upside-down world, Casey's alive! It's place where nothing gets lost. No wonder everyone here is so happy. Or are they? When Fred's sister joins him in the upside down world, the stakes suddenly get way higher"--Jacket flap.