Church of England Reverend Charles Fortescue (Palin) works as a missionary in Africa for ten years, then returns to England in the spring of 1906. As the ship docks, a fellow passenger, later identified as Lady Isabel Ames (Smith), bumps into him by accident.
Charles is to wed Deborah Fitzbanks, the daughter of a fellow clergyman. She was only a child when he left, but is now a young woman eager to be married and have lots of children; however, she dislikes being touched by him.
The Bishop of London gives him a new assignment, to set up a mission to rescue the women of the evening who frequent the London Docklands, but cannot offer him any funding. To assist him, Deborah writes to Lord Ames, the richest man in England. Charles reluctantly calls at their enormous mansion. The place has so many rooms that Slatterthwaite, the longtime butler, constantly has trouble finding his way about. He does eventually manage to bring Charles to the Ameses. Lord Ames loathes missionaries (among other things), but Lady Ames is inclined to contribute, especially as she finds him attractive (and tells him so). Somewhat alarmed, Charles tries to leave, but she insists he spend the night.
Late that night, she comes to his room. He tries to get her to leave, but when they hear someone coming, she hides under his bed covers. It turns out to be Slatterthwaite, lost once again. After he realises that this is not his room, he departs. Isabel then takes advantage of the situation to take advantage of Charles. Satisfied, she funds his mission.
Charles industriously sets to work, but the first prostitute he speaks to is highly skeptical. When he insists he does not look down upon her, she challenges him to prove it by sleeping with her. Apparently he does, as word quickly spreads of his unorthodox methods, and his mission is soon filled with young women. When Isabel pays a visit, she discovers him exhausted and sleeping on the floor, with three naked women in his bed. She cuts off her contributions. The women resume their trade to keep the mission going.
When Charles tries to explain himself, Isabel states that she was hoping he would help her to change her life (Lord Ames, it turns out, does not have anything physically to do with her), and now she threatens to do it herself. (She also reveals that she herself was once a fallen woman.) From this, Charles correctly guesses that she intends to have her husband murdered. He races to their Scottish estate on the day of his wedding and manages to foil a hunting "accident" by Corbett, an ardent admirer of Isabel.
Meanwhile, the Bishop of London receives numerous complaints from other denominations about Charles's unusual methods. He gives Charles two choices: leave the mission or the Church. Charles chooses the latter, and is joined by Isabel. Photos at the end of the film show that they have two children together.Michael Palin as The Reverend Charles Fortescue
Maggie Smith as Lady Isabel Ames
Trevor Howard as Lord Henry Ames
Denholm Elliott as The Bishop
Michael Hordern as Slatterthwaite/Narrator
Graham Crowden as The Reverend Fitzbanks
David Suchet as Corbett
Phoebe Nicholls as Deborah Fitzbanks
Roland Culver as Lord Fermleigh
Rosamund Greenwood as Lady Fermleigh
Timothy Spall as Parswell
Neil Innes as Singer in Gin Palace