Anne Rice's Lasher once again follows Dr. Rowan Mayfair, who in the previous novel in the series The Witching Hour, traveled to New Orleans after the death of her mother. While in New Orleans, Dr. Mayfair marries and has a child with a man named Michael. But Dr. Mayfair is kidnapped and impregnated by an evil spirit called Lasher, who is the namesake of Rice's second novel and is focused on becoming flesh and blood once again.
At the start of Lasher, Dr. Mayfair has disappeared without a trace, which leaves Michael in a deep state of depression. He takes antidepressants, but they don't help him much. One day, a young woman named Mona Mayfair, a powerful witch, meets and subsequently seduces Michael. This ultimately takes Michael out of his depression and causes him to commit to finding Dr. Mayfair, who he is now convinced didn't leave willingly.
In fact, Dr. Mayfair hadn't left willingly. She is a prisoner of Lasher, who has tried and failed to impregnate her a couple of times. Finally, though, on Lasher's third attempt, he can inseminate Dr. Mayfair. As Lasher and Dr. Mayfair travel across Europe, Dr. Mayfair is able to determine that Lasher is a different species (called the Taltos). She also determines that she has a genetic abnormality which allowed Lasher to take over her fetus in the previous novel and be born in human form.
Eventually, Lasher and Dr. Mayfair return to the United States. There, Lasher sets out to impregnate other female members of the Mayfair family. But each Mayfair woman Lasher impregnates swiftly die and their babies are lost.
Michael is finally able to locate Dr. Mayfair, and the two reunite at the home in New Orleans. But Lasher, who is upset and determined to be with Dr. Mayfair once again, confronts her and Michael at their home. Unlike the last novel, Michael is able to kill Lasher, who he buries in their back yard. However, Dr. Mayfair also kills the child she had with Lasher.
