Lou is tired of being teased by his older brothers and getting lectured for what his parents call "bad choices." When his birthday comes and all he gets is a dusty old book and a card with his name spelled wrong, Lou makes a secret wish as he blows out his birthday candles: to be a huge beast. That way, his family would treat him with more respect. Soon afterwards, though, his body starts doing weird things--like growing hair on his feet, sprouting extra-sharp fingernails and craving foods like raw steak. Could it be his careless wish coming true? Tired of hiding all these strange changes, and worried he might actually be dangerous, Lou decides to run away. But, with the help of a surprising ally, Lou finally discovers that he belongs in his family pack after all.