In the fourth Angels of Mercy novel, New York Times bestselling author CJ Lyons returns to an ER under attack as the lives of four very special women hang in the balance...

With Pittsburgh snarled by a New Year's Eve blizzard and Angels of Mercy Hospital cut off from the outside, staff and patients are at the mercy of armed gunmen. Their target is Dr. Gina Freeman, who is holding vigil over her wounded fiancé, Detective Jerry Boyle.

Trapped inside with her are ER charge nurse Nora Halloran and fourth-year medical student Amanda Mason, on the last night of her rotation—if not her life. Stranded outside the hospital walls is ER physician Lydia Fiore, whose past holds the secret the hitmen are willing to kill for. With patients, staff, and loved ones held as hostages, the power out, and cold-blooded killers in control, no one may live to see the New Year...

Critical Condition includes a teaser for the first Angels of Mercy novel, Lifelines.