The Road. The World Without End, #1

Left alone in a world overrun by the undead, Olivia Evans faces a dangerous choice when she meets four soldiers on the road. She can trust armed strangers or continue alone. Traveling with the men may offer protection, but Olivia soon discovers that they do not fully trust one another. Each carries his own history, his own loyalties, and his own reasons for keeping his distance. Yet as the miles pass and every stop brings new danger, the fragile bonds between them begin to deepen into something none of them expected.
Olivia set out only to survive. But the four men beside her may come to mean more to her than safety. Much more than any of them expected to find in a world like this.