An original story, not a novel
Reacher adapts Lee Child's novels. Neagley is different. It's an original mystery written for Prime Video, not an adaptation of any one novel. It was created by Nick Santora and Nicholas Wootton, who are the showrunners.
Where the character comes from
Frances Neagley is a book character. She first appeared in Lee Child's 2002 novel Without Fail and has turned up in several more books since. The show borrows her, her Army background and her friendship with Jack Reacher, then gives her a new case.
What about the plot?
The cult-like farm and the drug at the centre of the case are made up for the show. We haven't found any report linking the story to a real event.
The novel is coming after the show
The order is flipped from usual. Lee Child is co-writing a Neagley novel with Yasmin Angoe, Zero Margin, due in March 2027. It's a separate story from the TV mystery.
Where to start
If you want to know who she is before you watch, see who is Frances Neagley.