After the wildly successful "Harry Potter" series of novels that then turned into a film franchise and even an Orlando theme park, JK Rowling's books became grimmer and darker, as the British author sees the first adaptation of a non-Potter book in the BBC.

Only a few months after the original release of "The Casual Vacancy," the first of JK Rowling's books after the incredibly successful saga about a boy wizard in Hogwarts School of Witchcraft and Wizardry, major broadcaster BBC commissioned a miniseries about the novel, a political satire about the open seat in as councilor in a suburban West Country town called Pagford.

According to The Guardian, the JK Rowling's books adaptation, her very first that's not related to the "Harry Potter" saga in any way, will see a major plot change in the ending, as the screenwriters for the BBC miniseries thought it would be too "grim" to leave it the way it was, as there are things that work in books but not necessarily on television or film.

"I met up with Jo in Edinburgh to talk about the book, writer to writer," said Sarah Phelps to newspaper The Telegraph, after having written the small screen adaptation to the first of JK Rowling's adult books. "I told her what I thought the book was about, which characters really leapt out at me, and how I might shape the series and she just said, 'Great. That's your job.' I suppose, having seen Harry Potter adapted, she must be used to it, but it still meant a lot that she trusted me just to get on with it."

As The Daily Mail reports, "The Casual Vacancy" received mixed reviews upon its release, but became a public favorite, selling 125,000 copies in its first week, quickly turning into the fastest-selling hardback book in the United Kingdom in the last few years.

The adaptation to the first adult-themed of JK Rowling's books will begin airing in the United Kingdom on Sunday February 15 in BBC1, though it is unclear when it'll air in the US.