Two years after a Coronal Mass Ejection struck Earth, killing billions and destroying all vestiges of modern technological life, Dr. Riley Poole struggles to keep her family and career together as she continues the desperate search for her missing daughter, Julia. 
When Riley gets news that Julia is alive in an internment camp on hostile soil, she abandons her post with a field medical unit and races to Julia's rescue. When old enemies resurface, she runs into more trouble than she can handle, but with the aid of old companions and new, she regains hope of rescuing Julia.