Bonecrack by Dick Francis

In the middle of the night, two masked men break into Neil Griffon’s home and abduct him. He quickly discovers that unless he agrees to their unreasonable demands, they will destroy his father’s precious horses and racing stable—and, ultimately, Neil himself. Returned to his father’s stables, he must find a way to bring down these criminals. Because having to choose between his integrity and his life is no choice at all…