Suddenly and disastrously, smallpox strikes the town of Kingsbourne in the south of England. For Dr. Steven Monks, this means the postponement of a well-deserved holiday with his wife.
As the sickness spreads and takes its toll, the doctor's own life shows increasing symptoms of another kind of trouble one dating back to a night spent with Ruth, a colleague's wife. His is a moral sickness, and before it is through, it changes lives as drastically as the epidemic which scourges the town.
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