La leyenda de Greg

Ordinarily, thirteen-year-old Greg Belmont likes being ordinary, which would be fine, except that every Thursday his family's ancient curse strikes. Last Thursday a polar bear attacked him at the zoo. Now, however, Greg finds out the truth--he is actually a fantastical Dwarf. His dad gets kidnapped by the Bro-Troll and Greg must travel to the mythical world beneath Chicago, where Greg finds himself in the middle of a conflict of magic between the Dwarves and Elves.