There really is no poorly written Dick Francis book, but Enquiry is among the best of the best.
Jockey Kelly Hughes is accused of throwing a race, and is warned-off, but doesn't take it lying down. Instead, he turns over every stubborn rock until he nearly falls off the edge of a vehicular cliff, when he probes too closely.
Snobbish Trainer Dexter Cranfield practically falls apart, as he is also warned off, but Kelly is resourceful, and pushes him to stay the course.
Cranfield's beautiful if stuck up daughter, Roberta, starts to pal around with plebeian Hughes, and things might never be the same.
The person who framed the two men is on the loose, and no one is safe until the mystery is solved. It might sound cheesy, but Francis keeps you glued to the page, relentlessly.
Hats' off to the late great Dick Francis; another of his entries, Enquiry, wins.