Headstrong Megan Roberts, newly arrived district nurse in a South Wales town, is ready to fight the hypocrisy of a tightknit community set in its ways and suspicious of change.

The district nurse is convinced that whatever is causing the epidemic is being carried in the town's water supply. But how can she prove it in time?

Megan finds her nursing skills needed in an unexpected way on the farm, and is summoned to face an angry charity committee.