Holmes' former protégé, Kitty Winter, warns him of a killer who is eliminating everyone involved with a case they worked on together in London. Watson discovers that Kitty has a life changing secret.
Violet files for joint custody of Lucas, but Pete hires an attorney and fights back, dragging everyone at the practice into the trial.
The doctors venture into controversial territory when an unexpected new hire at Pacific Wellcare causes Naomi to struggle with the idea of genetically designing babies. Meanwhile, Violet decides to try electric shock therapy on a patient.
Sam convinces Violet to help plan Maya's wedding when Naomi refuses to take part, tensions between Addison and Sam rise.
Addison clashes with Sam's new girlfriend, Vanessa, over treatment for a patient whose life, and those of her unborn triplets, hangs in the balance.