Mary Jekyll, alone and penniless following her parents' death, is curious about the secrets of her father's mysterious past. One clue in particular hints that Edward Hyde, her father's former friend and a murderer, may be nearby, and there is a reward for information leading to his capture - a reward that would solve all of her immediate financial woes. But her hunt leads her to Hyde's daughter, Diana, a feral child left to be raised by nuns.