“I’m a writer, not a detective,” says Agatha Christie (Ruth Bradley) in a new trailer for “Agatha and the Truth of Murder.” Enlisted by a fan to help solve a murder, the mystery writer finds herself hunting a killer “more cunning and dangerous than her fictional creations,” the film’s synopsis hints.

After reluctantly agreeing to help investigate the murder of Florence Nightingale’s goddaughter, Agatha disguises herself to question a handful of suspects with motive. Local law enforcement seem unenthusiastic about her involvement in the case.

“Guilt,” “Humans,” and “The Fall” are among Bradley’s previous credits.

Last year it was reported that “Big Little Lies” exec producer Bruna Papandrea and her production company, Made Up Stories, has a Miss Marple series in the works based on Christie’s 12 books and 20 short stories about the small-town amateur detective. No word on whether the project is still in development.

“Agatha and the Truth of Murder” premiered on TV in the UK in 2018 and is now available on VOD and DVD in the U.S.