From 1994, this is probably my second-favorite Dick Francis novel (after Proof).
The narrator, Thomas Lyon, is visiting a dying old friend, a blacksmith who he knew long ago during a brief jockey career. Delirious from drugs and pain, the blacksmith mistakes Thomas for a priest, and incoherently seems to confess to a past crime.
Thomas is an up-and-coming movie director, and he just happens to be in the area making a movie. It just happens to be based on a fictionalized version of past events: the young wife of a horse trainer was found hanged in a stable. Was it murder or suicide? To this day, nobody knows.
But someone's apparently worried that the movie might illuminate how that death occurred. People are threatened, nearly killed. Including, since he's the Dick Francis hero, Thomas. The production is also in peril because the screenwriter doesn't like the changes Thomas is making to his version of the story, and badmouths him to the press.
So Thomas faces daunting odds: how to bring in the movie on time and budget, true to his artistic vision, while at the same time unravelling the mystery of what happened decades ago. Also, while staying alive.