The world went dark, but Mackenzie was one of the ones who had prepared for it. Not everyone is as fortunate. Prescription drugs are no longer available, and Mac's best friend is a type 1 diabetic. She manages to find someone who can make insulin the old-fashioned way, but she still has to get it to him before it's too late. That means leaving the safety of her hidden farm and travelling hundreds of miles to get there, without getting killed along the way. Meanwhile, her daughter is forced to contend with one disaster after another.