 PC Rowan is on loan to the CID to investigate local gangster Frank Armstrong. But Rowan has other things on his mind as well. Katie is getting christened and he gets a visit from Jill Criddle, an old friend and colleague from the Met. By request of the CID she teams up with Rowan as his  floozie . They soon discover that Armstrong is spreading out his activities to include race horses. Armstrong is not the only one interested in race horses. Greengrass and his friend Billy Black, also known as The Horse Doctor, want to improve the chances of a certain horse in a race. Incidentally Armstrong is also very eager to talk to Black and has sent to goons to get hold of him. Unfortunately Black knows that Nick and Jill are cops!