In Boston, there's a killer on the loose. A killer who targets lone women, who breaks into their apartments and performs terrifying ritualistic acts of torture on his victims before finishing them off. His surgical skills lead police to suspect he is a physician - a physician who, instead of saving lives, takes them. But as homicide detective Thomas Moore and his partner Jane Rizzoli begin their investigation, they make a startling discovery. Closely linked to these killings is Catherine Cordell, a beautiful medic with a mysterious past. Two years ago she was subjected to a horrifying rape and attempted murder but shot her attacker dead. Now she is being targeted by this new killer who appears to know all about her past, her work at the Pilgrim Medical Center, and where she lives. The man she believes she killed seems to be stalking her once again, and this time he knows exactly where to find her.