In the novel The Floating Admiral, Mrs Davis is the proprietress of the Lord Marshall, in Whynmouth. She has the reputation of being the biggest talker in Whynmouth. According to Constable Hempstead, no one "can get a word in edgeways when she's about". However, Mrs Davis herself claims that her motto is, "Keep a still tongue in your head and you can't go far wrong."
Mrs Davis' husband does not appear in the novel, but she mentions him to Inspector Rudge, saying that he used to say, "Cut the cackle and come to the horses". As she only speaks of him using the past tense, this may suggest that he has passed away by the time of the events of the novel.
After the murder of Admiral Penistone, Inspector Rudge interviews Mrs Davis, because he wants to know what gossip had been spreading about the Admiral.
Mrs Davis is described as being a "jolly, good-humoured-looking woman of fifty". She has a high-pitched voice, and wears a gold locket, and several rings.
When Inspector Rudge comes to interview her, Mrs Davis says that she knows him by sight, and that she knows everybody "in these parts". She first offers the opinion that the weapon that was used to kill the Admiral was an Italian stiletto, and that whoever killed the Admiral had been in Italy. However, she says that the person could not be an Italian, as they would have been noticed in a place like Whynmouth, where there are not many foreigners. She later expresses the opinion that Arthur Holland is not the murderer.
Mrs Davis tells Inspector Rudge that Admiral Penistone and Sir Wilfrid Denny were acquainted, and that Reverend Mount's wife had left him and their children years before.
Mrs Davis also tells Inspector Rudge that Admiral Penistone had called at the Lord Marshall the night before his death, and had asked for Arthur Holland, who was staying there. The Admiral had then said that he had a train to catch, and would not have time to see Mr Holland.