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.

The keen young Ross McInnes makes blunders when handling his first case since joining the Branch.

Ross McInnes, eager for work, acts on a tip-off meant for Smith, who lets him have his head while keeping him on a long lead.

Three million English cigarettes are hijacked in France. The men of the I.B. go to work on the assumption that they could be on their way back to this country. The problem is when and how - and who?

Tom MacDonnell, a haulage operator, uses gas oil, duty twopence a gallon, in his lorries, but claims rebate on diesel, duty three shillings and sevenpence a gallon. When Meg meets up again with once steady boy friend Caesar Smith she finds that her emotions, her maternal interest and her loyalties are all placed under a cruel strain.

Larry Hagan is a good businessman, deserves all the trappings of success. Or so it seems until Smith and Campbell take a closer look and uncover a neat racket.

The import duty on antique jewellery is high. So evasion on a valuable item can look like a way to easy money - and become a difficult trade for the men of the I.B. to put a stop to.

Easy money is the usual lure in smuggling. But there can be other motives as Smith and McInnes discover when they dig into the past of a man who seems to have everything money can buy.

One case leads to another and Smith discovers the makings of a fraud that neither the I.B. nor the police can do anything about - until someone gets hurt.

Some contraband can kill, and when this happens Smith and McInnes need to go a step further than the police to cut the pipeline.

When whisky disappears from a bonded warehouse Smith and McInnes become involved in a very ingenious plan to defraud the Revenue.

Smith is investigating a firm of importers but when he becomes involved with the owner's daughter he finds himself in a most invidious position.

A child is shot by terrorists and the rifle used was made in Britain. Smith becomes emotionally involved in the case of illegal arms deals because of his personal experience of terrorists. But then, who are the terrorists?

When plastic explosives are used by the so-called I.R.A. it becomes obvious that their supplies are coming into the Republic from Britain. McInnes and Smith investigate and find that even the most charming of men can be dangerously irresponsible.