Twelve-year-old Mack MacAvoy suffers from a serious case of mediumness. Medium looks. Medium grades. Medium parents who barely notice him. With a list of phobias that could make anyone crazy, Mack never would have guessed that he is destined for a more-than-medium life. And then, one day, something incredibly strange happens to Mack. A three-thousand-year-old man named Grimluk appears in the boys' bathroom to deliver some startling news:...