The series begins in 1895 with Dr. Eleanor Bramwell, working in a London hospital. She is treated as an inferior by the male doctors, and her opinions are often ignored. After a disagreement with a senior doctor, Eleanor is dismissed. Her father, Dr. Robert Bramwell, recommends she join him in his private practice of rich, elderly clients. Fortunately, Eleanor receives a better offer. Lady Peters, a friend of the family, offers to fund a small hospital in a London slum, where Eleanor will treat the impoverished locals. Together, Eleanor and Lady Peters establish The Thrift, a free hospital with six beds. The Thrift is named for its location on Thrift Street.

In the Second Series, The Thrift attempts to survive without Lady Peters' guidance, management and financial assistance. A new character, Dr. Finn O'Neill is introduced when a cholera epidemic occurs in the area and Finn assists in the hospital.

Series Three begins a year after Finn's leaving. He has returned to England for a conference and takes this opportunity to visit Eleanor. Eleanor confirms that she still wishes to be married to Finn in a year when he permanently returns to England. Mr. Marsham considers taking a better position in Edinburgh, but remains at The Thrift.

Eleanor allows The Thrift to perform medical check-ups on soldiers, which leads to her meeting Major Quarrie. Eleanor becomes obsessed with locating the child of a patient at The Thrift and searches the slums.