Susan Watts a young, beautiful blonde woman is found strangled in an alley. She was running in her nightgown before she was murdered. Lanie has a strange feeling about this one. When she finds out that Susan had many similarities to Pam Hodges, the woman who was surgically enhanced to look like Lanie by Dr. Kelly Niemann and then murdered, her suspicions are confirmed.
Believing that this case is connected to both Dr. Kelly Niemann and possibly 3XK, Beckett asks Gates to let Castle help on the case. Gates gets the DA to agree to let Castle back for this case only.
Dr. Niemann claims she never met Susan Watts, however she does donate heavily to an organization, New Start Horizons that helps women who have been in prison find jobs. Hospital footage shows a woman who looks exactly like Susan Watts leaving with a bag from Dr. Niemann’s office but it’s from after Susan’s death. She gets into a truck and the man driving looks exactly like Jerry Tyson, 3XK.
The truck belongs to Michael Boudreaux and when they get to his apartment they find Jerry Tyson and arrest him. But Tyson is claiming to be Michael Boudreaux who had plastic surgery done by Dr. Niemann. His fingerprints even match Boudreaux’s in the system.
With all of the evidence involving Tyson having been stolen, including DNA samples, Castle and Beckett head to Tyson’s childhood home where they find his foster mother, Gretchen Cutler. Tyson’s birth mother died and his father (also deceased) left Jerry with Gretchen. She turned him over to the State when he was 9-years-old. Although Jerry took most of his things, she kept one box of childhood moments, including a baby tooth. They use to to get DNA.
In trying to find the real Michael Boudreaux, Beckett runs into Amy Barrett, Boudreaux’s girlfriend and Susan Watts look alike. When she won’t talk to Beckett, she makes her taker her card. Later, Amy calls Beckett. She scared. Beckett leaves to bring her in.
Castle sits down with Tyson and profiles him. He has a photo of a young Gretchen Cutler and she looks just like Susan and Amy. Dr. Niemann is making victims for Tyson. But when the DNA results from the baby tooth don’t match the man they have in custody, they are forced to let him go.
Jerry Tyson (or is his Michael Boudreaux?) leaves hand in hand with Kelly Niemann. Castle realizes that they both wanted to be at the precinct. He tries to call Beckett but it only goes to voicemail.
While Beckett is searching for Amy, someone drugs and grabs her from behind.