M/S of a class room in the Waterguard Training Centre of H.M. Customs and Excise. Around a large table eight "newly joined assistant preventive officers" sit taking notes. In front of them is their uniformed instructor. He is using a stick to point at a blackboard on a easel. On the black board the word 'smuggling' is written in large letters, beneath this are several bullet points. Behind the instructor is a large model of a ship in a glass cabinet. C/U of the instructor standing in front of the blackboard, on the desk in front of him are two models. He picks up one of the models and shows it to the class. C/U of the model. The model is a cross section of a ship's hold. By removing a panel inside the model the instructor can reveal a potential hiding place for contraband. The instructor moves the model to one side and picks up a hollowed block of wood that contains a secret compartment. The instructor shows the hidden compartment filled with watches and jewellery to the class. Panning shot to the next example of a concealed compartment. C/U of three young students crowded around one of the hollowed blocks of wood. They examine the block before returning it to the instructor.
M/S of the instructor passing cameras around the group of students for inspection. The purpose of this exercise to assess the duty payable on goods entering the country. One student takes the camera, studies it and refers to a catalogue marked with the Queen's emblem and the word 'tariff'. C/U of another student taking a leather strapped watch for inspection. He looks at the watch before leafing through a catalogue. Panning shot along the table to a third student holding a pair of binoculars. The instructor is standing over him and also looks at the binoculars before walking off.
M/S of the instructor holding a bottle of gin. He holds the bottle upside down and shakes it before passing it to one of his students who also shakes it. The instructor uses his stick to point to the bubbles at the top of the bottle. By shaking the bottle the students can determine whether the liquid inside is harmless water or smuggled spirits.
M/S of the classroom. On the tables are petrol tanks - the students are inspecting them for hidden compartments. M/S of the instructor passing around various wooden pipes and cylinders to students standing on either side of him. C/U of a student examining a pipe before placing it on the table and picking up a man's brown leather shoe. C/U of the heel of the shoe. The heel opens to reveal a hidden compartment filled with white tablets - narcotics. M/S of the instructor holding up a long wooden marijuana pipe to demonstrate to the students how it would be used. The instructor places the pipe on the table and picks up a brown block of opium which he passes to the students to smell. According to the narrator "the distinctive smell of opium, particularly when damp, has been the downfall of many a dope runner". M/S of the instructor demonstrating where drugs could be hidden in a petrol tank. C/U of one of the students listening intently. M/S of the instructor holding a green petrol drum. He shows the inside of the drum to the students. He then takes a pile of photographs resting on the top of one of the tanks and distributes them. C/U of a photograph of a watch lined waistcoat. C/U of a black customs guard holding a book with a hollowed out compartment inside.
M/S of the instructor standing in front of the black board. He dismisses his class. They all stand and exit.