"Witness for the Prosecution" is a typical murder mystery originally written in short story form by Agatha Christie. The story takes place in a small English city where Leonard Vole and his wife, Romaine, struggle to make ends meet. A wealthy woman named Emily French is murdered. Because Vole had spent much time with Miss French in the previous weeks, he is the prime suspect. Vole finds a good council and pleads his case to the judge. Then there is a twist - Vole's wife ends up being a witness for the prosecution. Some years later, the short story was made into a movie. During this process three major changes were made: the characters" names were changed, the story changed from an investigation to a courtroom defense, and a surprise ending was added. .
The biggest change I found in the characters" roles and their names is the switch of solicitor and barrister. In the short story, the solicitor is Mr. Mayherne. He takes the case for Leonard Vole and handles most everything in the investigation. Since Sir Charles is the barrister, there is only one short paragraph set in the courtroom in which he plays the lead role in Vole's case. In the movie, however, Mr. Mayhew is the solicitor. He has a very minute role since most of the movie is set in the courtroom. Although his doctors have advised him otherwise, Barrister Sir Wilfred Robards handles most everything for Vole's defense. .
Sir Wilfred has a heart condition. He is told that he should "take it easy." He is not to drink, smoke, or put himself in high-stress situations. Thus, Sir Wilfred is given a nurse, Miss Plimsoll. She is always nagging Sir Wilfred to do what is necessary. For example, he is supposed to take a nap everyday, take his pills regularly, and is definitely not supposed to take stressful cases. Miss Plimsoll ends up going to the courtroom for the case hearings to make sure Sir Wilfred does as he is supposed to. She sets the buzzer on her watch, which is loud enough for all in the room to hear, so Sir Wilfred won't forget to take his medicine.