I inhaled the first book in this series, Heartsick. It's a strangely macabre account of a police detective and his bizarre "relationship" with the serial killer he attempted to capture and in the process became her prisoner. She tortured him, removed his spleen, and forced him to drink drain cleaner a teaspoon at a time. She eventually saves his life and turns herself in, but Archie's scars are more than skin deep. He pops pills just to make it through the day and hasn't been able to resume a normal relationship with his wife and children. He's obsessed and tied to the serial killer in a totally sick way. He sees her every week in prison because she revels names and details of her victims to him. And now he looks to her to help solve the next great case, another serial killer on the loose.

Sweetheart begins where Heartsick left off. Archie is determined to rid himself of Gretchen's (the serial killer's)strange hold on him. He is reunited with his family and even feels happy some days. But Gretchen escapes and he is determined to be the one that brings her in. This is not my usual cup of tea but I was fascinated by the story and couldn't put it down until I had turned the last page.