The 'Darcys and the Bingleys' is set in 1803, shortly before the ending of Pride and Prejudice by Jane Austen. It becomes with the upcoming nuptials of two couples: Mr. Darcy and Miss Elizabeth Bennet; and Mr. Bingley and Miss Jane Bennet. Three days before the wedding (which is briefly described in the original novel on which this is based), Charles Bingley approaches his old friend Fitzwilliam Darcy for some marital advice. This begins the first segment of the book, "A Bit of Advice," which shows the transition of the two couples from separate individuals to husbands and wives, brothers and sisters.
The second segment, "The Question of Consent," opens in 1806 and concerns a possible suitor, Lord James Kincaid, who has proposed to Miss Caroline Bingley, Charles' older sister. Mr. Bingley enlists his friend Mr. Darcy to help him investigate this character, just returned from Australia with a newly-minted fortune. Is Caroline in love? Is Lord Kincaid telling the truth?
The book is set in England, but why 1803? There are two traditional "datings" for the events of Pride and Prejudice: 1796-97 and 1811-1812. Both have a reason but neither have any actual validity. The novel itself never gives a single date (except days and months, in letters, and an occasional mention of what season it is) but only helps us calculate that the events take place over about 14 months, not including the last chapter, which summarizes some future events.
The reason for the first date, 1796, is because that was the year that Jane Austen began work on First Impressions, the original version of Pride and Prejudice, which does not survive today but is mentioned in various letters she wrote to her sister. The 2005 movie was set in this year.
The reason for the second date is because it ends the story in December 1812, and Pride and Prejudice was published in 1813. The 1995 miniseries was set in this year.
When placing the story within its setting, the only actual thing the author is bound to is from about 1790 to 1815. Before 1790, some of the social customs, mentions of fashions, and amounts of money wouldn't have made much sense, especially the further back you go. Past 1815, all of the bits about the militias marching in towns doesn't make sense, because Waterloo has happened and the French defeated, and most of the British army has been disbanded or sent to fight in colonial wars in Africa or Asia. Within that time span, you can set it whenever you want. I chose 1803 for pacing reasons in later stories, which have to occur alongside certain historical events.
"A Bit of Advice" was one of my first forays into Pride and Prejudice fan fiction. Intended to be a humorous short story, it quickly became something more. My intent was to tell the story of Darcy and Bingley's friendship, which was so integral to the background of Austen's work yet so ignored in sequels and fan fiction. Pride and Prejudice is from Elizabeth's perspective and so we see little of it, but as the plot reveals itself, we learn that behind the scenes, the friendship was one of the drives towards (and at one point, away) from matrimony.
When Mr. Bingley is introduced in the opening pages of Austen's work, and the reader has no previous knowledge of the story, they would assume that he is going to be the central protagonist. He arrives at the assembly bringing a friend, who it turns out is a jerk, and probably not all that memorable. This friend is Mr. Darcy, the sucker-punch protagonist, and the ultimate romantic hero, but it takes the reader (and Elizabeth) some time to figure that out. Only late in the book does Bingley reappear and the two couples who probably would have gotten off to a good start in the first place had Darcy been in a better mood at the assembly finally marry.
I wanted to give Bingley his moment in the sun, but of course he has to share it with Darcy, or there isn't going to be much reader interest. And Darcy has to share it with Elizabeth, or there won't be much reader interest. And we can't leave out Jane, because that's just not fair at this point. Then they meet and talk to people beyond the four of them, and eventually I have a swelling cast that I don't know what to do with except write funny dialogue.
"A Question of Consent" was a challenge. Having united the two couples, I wanted to see if it was possible to make Caroline Bingley, arguably a villain in the book (she does some nasty things), into a sympathetic character. Whether I succeeded or not is your decision, if you buy the book or read it online.