Dig two graves

In his twenties, Ethan Holt won the decathlon at the Olympics and was jokingly nicknamed "Hercules"; now, in his late thirties, he's returned to his ivy-covered alma mater to teach, and to raise his young daughter Skip as a single father. After a hushed-up scandal over his Olympics win and the death of his wife in a car accident five years ago, Ethan wants nothing more than to forget his past. Skip is not only the light of Ethan's life--she is his life. Then, Skip is kidnapped. A series of bizarre ransom demands start coming in that stretch Ethan's athletic prowess to its limits, and he realizes with growing horror that they are modern versions of the Twelve Labors of Hercules, demanded in tricky, rhyming clues by someone who seems to have followed every step of Ethan's career.