The narrator of this historical novel, Anna Frith, works as a servant in the household of the local minister. The story recounts the horrific events in a plague-ridden village of 17th-century England. Anna, having lost her young husband in a mining accident, loses both her sons to the plague, as well as a boarder in her household who seems to have been the first case in the village.

After these losses, she stays her grief by tending the sick in many families. Particularly after the village works out terms of quarantine with the earl, no help but food and supplies comes in from outside. She learns much from the local herbalists, two midwives whose work she carries on after their violent deaths. In this work she develops a close partnership with the pastor's wife.

The story takes us through the whole trajectory of loss, accusations, spiritual struggle, shared grief, creative adaptations, and eventually emergence from sickness and quarantine. Anna's own journey takes some surprising turns as her confidence and clarity about her own mission grow and deepen.