The thirteenth season of the American fictional drama television series ER first aired on September 21, 2006, and concluded on May 17, 2007.

In the aftermath of the shootout Abby delivers a premature baby while Sam suffers a terrifying ordeal at the hands of her ex-boyfriend.

Meanwhile, the show's longest-serving character Kerry Weaver departs when Kovač is forced to make budget cuts which threaten her job.

Abby's trauma puts her into pre-term labor, and when the risk of placental abruption becomes a reality, her baby is born two and a half months prematurely.

After a rough chase from local police, Steve and his co-conspirators decide to hide out with hostages Sam and Alex.