The Dying Days universe has quite an expanse to it, so I'm going to focus on the story line that follows Darlene Bobich.
The beginning of Darlene's journey begins in Darlene Bobich: Zombie Killer. When we meet her, she's living in Maine and she's been forced to kill her father, who had gone zombie. Sadly, she had to do the deed with the gun that her father had given her and taught her to shoot with.
Once Darlene comes to realize the world has gone to hell in a handbasket, where she lives is too far gone and she sets out to escape the town she had been living in. The neighbors prove to be no help, but only because "NOM!" has set in.
Darlene finds herself at the local mall in search of a quieter weapon, news and other supplies. She does meet with some former co-workers and manages to get a small piece of normal until zombies appear.
After a couple more duds at a stadium and a store where the employee is set on committing arson, Darlene finds herself in Buffalo, NY freezing her butt off. Soon she has more to worry about when she comes across some not so nice people set on making her stay. It takes some time, but Darlene manages to dissuade them of the notion of keeping her around and she's back on the road again.
Soon Darlene has a road companion, but it's short lived and she's stranded in Connecticut. After a side adventure with some school children, we find Darlene in a group of survivors pulling guard duty in a convoy. This too becomes short lived and Darlene is left fending for herself in a library. She does have a companion while at the library, but an accident one night finds Darlene back on the road again.
The book closes with Darlene still on the road, headed to The Sunshine State.