The new neurosurgery center opens, and Nic is forced to work alongside Cain again; a heart transplant has an unexpected result; Bell asks Conrad to reexamine three patients who may have been poisoned.
A renowned pediatric cardiac surgeon proves unfit for surgery; a Dolly Parton drag queen collapses on stage; Nic and Conrad suspect a patient may be the victim of sex trafficking; Nadine delivers some surprising news to Devon.
Amaro suspects the boyfriend of a missing girl is involved with a gang; Sgt. Benson becomes the SVU's new commanding officer.
Benson is assigned a 24/7 security detail when William Lewis (Pablo Schreiber) escapes from prison and starts killing again; Benson must decide how much she is willing to sacrifice to save a child's life.
Drs. Manning and Rhodes suspect that two separate cases involving sick babies may be connected; a homeless patient's upbeat disposition enlightens Drs. Halstead and Charles; Dr. Choi and a Navy corpsman deal with the toll of gang violence.