Drayton, a perfectly normal and respectable businessman, is sacked from his job as general Manager of the Dynaflow company after only four weeks in office. The company has been bought out by a Mr. Purvis and the price is suspiciously low. Drayton contacts the I.B. and it doesn't take Smith long to realise that a colossal Purchase Tax swindle is in the making. The trouble is, how to prove it. And that's where Smith has to start playing the waiting game.

The Customs men at a Continental car ferry become suspicious when a man makes too many trips through their port.

Lying to the Customs men - whether about that extra packet of cigarettes or an expensive gold watch - causes more trouble than it's worth. Sheila and Dick Graham find this out when they lie about a valuable microscope found in their luggage, and set McInnes and Smith off on an investigation.

Sir John Dolan and Stuart Campbell are close friends. And we all need friends, don't we?

Ross McInnes learns that a good I.B. man must think of the Department above all things - even above friendship.

When Penman's flat is broken into by a young man, a chain of strange events leads the I.B. into a macabre and dangerous case.

Smith arrests two old clients and oversteps the mark. The two he has accused insist that he himself should be investigated.

Fortunes can be made from a leak of information from a Customs office. Smith and McInnes attack the problem from two sides, both with equal application.

Perhaps to be a good I.B. officer one should have no emotions at all. Ross McInnes finds this out the hard way.

When Paul Valery, an international con-man, has a mysterious visitor, the I.B. become involved with a very undesirable alien.

When Paul Hasek, a foreign diplomat, is caught in a compromising situation, his privileged position is used as a cover for smuggling.

Any way of reducing the price of mink coats would be welcomed by some women, even if it means depriving the country of revenue.

When a man collapses in a Customs hall he is found to be carrying a large quantity of gold.

Smith is involved in butter smuggling between Northern and Southern Ireland and he and McInnes find themselves up against a very professional operator.

A man called McGeely arrives in Scotland but cannot leave his ship because he has no papers. He claims he comes from Glasgow and mentions Sauchiehall Street as proof. But as the Customs men point out, everyone all over the world has heard of Sauchiehall Street. Smith and McInnes are after some smugglers who are bringing high quality jewellery into the country in small quantities. McGeely is given a piece to smuggle ashore but when he vanishes from the ship the smugglers have about as much idea as the Revenue men about where to find him. Who gets there first?

The I.B. are confronted by a case of 'the worst kind of smuggling'. Campbell puts Ross McInnes on the trail of the client concerned. Ross traces him as far as the Inner Hebrides but arrives too late. It seems he cannot pursue the case any further - it's a dead end. He returns to report his failure to a furious Campbell.

Last week Logan's death brought Ross to a halt. This week Smith resumes the search for the man who supplies the peddlers.

Johnny Cain is back again and Smith's holiday in Switzerland develops into another case for the I.B.

A labourer is taken to hospital having been poisoned by a bottle of illegal whisky. Ross McInnes investigates.

Smith is faced with a very difficult moral problem when he is informed that there are several illegal immigrants working at the docks.

The I.B. are called in to assist when the Waterguard are being annoyed by the activities of Miss Stella Bruce, a rich young playgirl.

A huge combine is selling smuggled goods in working-mens' clubs, but there seems to be no way for the police or the I.B. to break the organisation.

Pressure on a colleague leads the I.B. to examine the sport of kings.

A family reunion sets Smith off on the trail of an illicit brew.

""Pull up the ladder, Jack"" could well be the Big Feller's family motto.

A dangerous man escapes from jail and Smith becomes involved.