It is 1665 and Mall Percival is a shepherd girl living in a Derbyshire village. She tends her flock, spends time with her best friend and teaches her young suitor to read. But one day a parcel of patterns, meant for a new dress for the pastor's wife, wings its way from London.

The parcel carries an infection that spreads with horrifying speed. Herbal teas and open windows are the only defence against the sickness. Yet the villagers make a brave and selfless decision: to isolate themselves from the rest of the country. It is a lockdown that saves the neighbouring towns, but at heart-breaking cost to Mall's world.

Based on the true events of the village of Eyam, this is the story of a courageous sacrifice that saved Derbyshire and beyond from a deadly virus.