It is based on the history of the small Derbyshire village of Eyam[4] that, when beset by the plague in 1666, quarantines itself in order to prevent the disease from spreading further.

Shortly after the arrival of a box of fabrics from London, Mr. Viccars develops a high fever, and starts exhibiting symptoms of the bubonic plague.

He begs her to burn all he brought with him to stop the spread of disease, but after his death, Mr. Viccars' clients come to claim their work and disregard the warning.

Over the following months, Anna and the rector's wife Elinor attempt to learn the uses of the contents of the Gowdies' physick garden, and take up the roles of village midwives.

They support each other through their struggles, and Elinor confesses as to why a high-born woman such as herself married a humble rector and devoted her life to helping the less fortunate.

She is completely incoherent and in a catatonic state by the time she is brought out in the morning, and the rector postpones dealing with her crimes fully until the plague is over.

However, the service has barely begun when a deranged Aphra, clutching the corpse of her youngest child, attacks the congregation, fatally slicing Elinor's neck before turning the knife on herself.

After they make love, Mompellion confesses his own dark secret regarding his relationship with Elinor (He admits to never having sexual relations with his wife because of a sin she committed earlier in life), and Anna is repulsed.

He agrees to take her in, due to his despair at sex segregation in Islam keeping women and their husbands from seeking his aid during medical emergencies and labour.