When a mysterious girl attempts to stake her claim to the Snowcroft family fortune, Myrtle Hardcastle's father, a lawyer, is asked to help prove-or disprove-the girl's identity. Is she truly Ethel Snowcroft, believed to be lost at sea with her parents, or is she a con artist chasing a windfall? Myrtle is enthralled by the case, but Mr. Hardcastle's investigation takes a detour when he's hospitalized for a tonsillectomy-and then witnesses a murder. Or does he?

With Mr. Hardcastle incapacitated and possibly hallucinating, Myrtle must step into the breach, and find the murder victim and the real Miss Snowcroft before the killer comes after her father.

With stakes this high, sleuthing puts Myrtle, her family, and the patients and staff of the hospital all In Myrtle Peril.