After the Clew Bay Boating Disaster of 1894, Achill Island, Westport and the whole of Ireland are hit with a tuberculosis epidemic. 12,000 people are dying annually from the disease and the funeral bells toll every ten minutes. Selfless doctors and nurses, are battling this enemy with little means. Dr. Charles Leo Birmingham, Westport Medical Officer is one who takes a particular stance to fight the “tubercle bacillus”. 

As well as tuberculosis, puerperal fever is causing the deaths of young mothers-to-be on Achill Island. District Nurse Mary Lee is summoned to Achill and is just as determined as Dr. Charles to make a difference and to end the suffering taking place.

Following her recent heartbreak, feisty tattie-hoker Kate Grealis, is awaiting the birth of her first baby and feels the immense weight of suffering around her. When a mysterious man arrives to the island, Kate begins to question everything.