P.C. Mike Jarvis is on the last few days of the Advanced Driving Course at Hendon. He gets on well with fellow team-member W.P.C. Sommer, but both of them cannot stand the third officer in their group, P.C. Penrose, the smug, over-bearing son of a ""Black-Rat"" (traffic officer) who sees himself as the best driver on the course, let alone in the Met. The trio attends a quiz night the night before their ""final drive"", the all-important test of their advanced driving skills, and Jarvis stops Penrose from drinking too much before the test. Battling station rumours that he is being re-assessed, P.C. Tony Stamp arrives at Hendon to check on Jarvis's progress - and is pleased when Jarvis passes his final drive easily - just a few points short however of becoming a Class 1 (Area Car) driver. A hung-over and ungrateful Penrose also misses out on his Class 1 rating, but W.P.C. Sommer makes it.