Sgt. Matt Boyden organises a simple obbo to catch a gang stealing an excavator from a building site. The situation is made more complicated when another gang turn up carrying guns and a man is shot and abducted. As Boyden angrily collars his snout, PC Garfield and PC Quinnan volunteer to check the hospital. Garfield's girlfriend Jenny is about to leave for South America, and he is keen to ask her to marry him, however Quinnan gets word that Jenny actually has feelings for him. As Garfield tries to organise a romantic dinner, DS Beech poaches Boyden's snout, but he too is given bad information. Garfield's dinner plans are a disaster, but he manages to catch Jenny at the nurses' home. He pops the question, but she declines, as Dave Quinnan watches from the car outside.