Spellcaster by George Bachman
Christine Daniel suffers in ways no sixteen-year-old should and no doctor has been able to cure her. The excruciating pains and high fevers debilitating her aren’t triggered by a physical cause but by visions of a youth calling to her while fleeing a mysterious man who means him harm. This could hardly be happening at a worse time, when she and her beautiful older sister Allison are making their début in high society, like other wealthy socialites seeking matches with titled but impoverished gentlemen in Victorian England.
Christine is convinced that to stop the visions she must somehow save this youth. But first, she has to find him. She needs someone who’d know how to locate someone through means outside the known senses, the paranormal. Unfortunately, the authorities have driven underground all but one of the country’s occultists, and the reason she isn’t hiding is the only reason she might help Christine, something she wants in return. Christine must convince Allison to marry the occultist’s lover, one of those impoverished gentlemen, so that the illicit pair can share her part of the family fortune while continuing their affair.
If Christine doesn’t stop the visions by saving the youth, the pains and fevers will eventually kill her. But if she does what the occultist wants, she will betray Allison to a lifetime of misery. Can she lead her sister into a marriage with a bad man if doing so is the only way to save her own skin – literally?