Deep below ground, there is a secret hospital for magical creatures. At Saint Philomene's Infirmary, all creatures are welcome?except humans. So when twelve-year-old human boy Chance Jeopard unearths a plot to destroy the hospital and its millions of resident patients, he is launched into the role of unlikely?and unwelcome?hero. His infinitely pragmatic and skeptical sister, Pauline, thinks it's all nonsense until she finds herself swept up in the mission. It will take all their wit and courage for the brother and sister to save Saint Philomene's?and escape alive!