https://www.amazon.com/Life-Blood-Ch....+black+kindle
First book in the Cora's Choice series
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She wanted life. He needed her blood.
Cora Shaw will do anything to live. Diagnosed with terminal cancer in her senior year of college, she is given a choice: Call hospice, or seek out a mysterious man who promises an impossible—and insanely dangerous—cure.
She knows him only as Mr. Thorne, a reclusive billionaire who seems full of contradictions. A man with strange, impossible powers over her.
A man, she discovers, who is not a man at all.