Is there any aspect of horse-racing that Dick Francis hasn't turned into a thriller? Yes: the horse-van business--with all those drivers taking horses to and from races, trainers, and breeders. And it's the basis for the freshest, moat energetic Francis book in years. Ex-jockey Freddie Croft, the likable narrator, owns and runs a fleet of 14 vans "zigzagging round England"--a tricky setup full of scheduling headaches. So the last thing Freddie needs is a couple of suspicious deaths around the place. First, there's the shady, middle-aged gent who hitches a ride on one of Freddie's vans and inconveniently drops dead (of natural causes, it seems). Then there's Jogger, Freddie's mechanic, who finds odd, empty containers attached to the undersides of several vans--and is soon thereafter discovered with a broken neck at the bottom of the inspection pit. And Freddie himself (in one of Francis's grand ordeal-set-pieces) is abducted and nearly drowned! What's going on? To find out, Freddie enlists the help of an undercover agent from Racing Security (an attractive older horsewoman) and--when strange chemical fluids become a key clue--his science-professor sister. Drug-smuggling? No--something far more interesting, with lots of curious, satisfying tidbits (from computer lore to Cockney rhyming slang) adding to the layered puzzle. Francis not only has a far-above-average plot this time. He has also taken the trouble to flesh out the supporting cast--the fussy and eccentric owners, the raggedy drivers, etc.--with his old-time brio. All in all, despite a sometimes sluggish pace: top-drawer Francis.