Twelve-year-old Valentina wants to focus on drawing the real world around her and hopefully get into art school in Bogotá one day, but Papi has spent his life studying Colombia's legendary creatures and searching for proof of their existence. So when Papi hears that a patasola--a vampire woman with one leg--has been sighted in the Andes, Valentina and her younger brother Julián get dragged along on another magical creature hunt.

While they're in the Andes, a powerful earthquake hits. Valentina and Julián fall through the earth...and find an alternate Colombia where, to Valentina's shock, all the legends are real.

To get home, Valentina and Julián must make a treacherous journey to reach this land's ruler: the madremonte, mother and protector of the earth. She controls the only portal back to the human world--but she absolutely hates humans, and she'll do anything to defend her land.