“It’s like watching child geniuses at play!” writes The New Yorker of PigPen Theatre Co.’s inventive storytelling. The company returns to the Old Globe stage with this Newbery Medal-winning tale of a mouse who wishes to become a knight. There’s a dungeon, a tower, a princess, and, as always, a nemesis—the rat Roscuro—plus music and stunning stage effects aimed at all ages. —L.J.