Dr. Melanie Morgan has not only found proof that vampires exist, she has discovered they might hold the key to curing the dark ravages of mental illness. After three months of working with her mysterious benefactor, a man she calls Mozart, she is on the brink of something. But another midnight visitor warns that instead of a breakthrough, she is inviting a breakdown, upsetting a tenuous balance between darkness and light. Her first desire had been to purge the darkness from tortured human souls. Will her last desire be to purge her own?