Secrecy is broken after a Mogul rig called Kelly's Eye, drilling far out in the North Sea, finds a small pocket of oil. It proves to be worthless, but someone from the rig has leaked the news to Press and television. When Brian Stead, Mogul's director of operations, orders the culprit to be found and sacked, it is Peter Thornton, the manager of North Sea operations, who has to investigate both on shore and aboard the rig itself.

Robert Driscoll is sent out to take over negotiations for an important Middle East oil concession after the mogul representative has been killed in the desert. Driscoll antagonises the men on the spot, particularly the area manager Charles Andrews, who thought that he should have had the job.

An oil refinery safety officer carries a heavy responsibility. So when Ron Smith arrives at Portlea to take over the post, most of his new colleagues treat his pomposity with an amused tolerance. If he chooses to run a fire drill on a Saturday - well, as he says, "conflagration is not predetermined. Emergency is always unexpected". If he insists on saying "one does not carry means of ignition inside the works area," when he means a box of matches, the fact remains that he is right. His efficiency must be beyond question. Personnel Manager Derek Prentice, consults Smith's personal file and is worried enough to send a report to Mogul head office. Prentice's secretary, Gwyneth, sees Smith as a lonely man who needs the concern and care she is prepared to give him. At head office they are too busy with preparations for a Royal tour of Portlea to pay much attention to apparently trivial problems but with the Royal party's imminent arrival, this particular problem could bring disaster.

In the oil industry, they gamble for high stakes. For 5 years, Mogul has been exploring two areas of West Africa, spending 30 million pounds without finding a single, viable oilfield. Now it is time to abandon the swampy coastal region, and Peter Thornton is sent out from London to take charge. But Sam Okeke, an African geologist, is convinced there is oil in the swamps. Thornton accepts his judgement and orders a wildcat drilling operation - and then Sam begins to realise just what he has started. He has told Thornton he is sure the drilling will tap oil, but as the latter says, it's a case of being "about a 100,000 pounds sure. More than a 1/4 of a million if we really get involved". For Sam, the exploration becomes a triple headache. He is now responsible for his friend Alan Boyd, too ill to be in the unhealthy swamp, will have to stay there longer, while Alan's lonely wife, Kitty, seeks solace elsewhere; and if Sam's judgement proves wrong, it can mean the end of his career.

The approach of parenthood can have a sobering effect on the wildest of men, and it is like that with Tosh Brinkwater (John Tate). At fifty-five, an age when most wild men have either been tamed or seem to be past redemption, Tosh, still the hardest-living seaman in the Mogul fleet, decides that the time has come to turn over a new leaf. About to become a father for the first time, he stops gambling with his mates, cuts down on his drinking, lays off his wild trips ashore at Port Said to see Busy Lizzie, and asks Brian Stead to find him a quiet job ashore so that he can be with his wife, Nora (Jane Hylton), and his child. But when you are part of the far-flung operations of a big oil company, even the best of intentions, the most carefully laid plans, can go wrong.

Mogul Oil has never traded in Germany, so the Director of Operations sends Driscoll (Barry Foster) to investigate the market.

The desert is like the sea. It takes possession of a man's soul. For a young geologist seeking to prove himself it is exciting. But like the sea the desert is dangerous.

Motor racing means excitement; it also means danger. Driscoll faces personal risk when he opposes Stead and tries to steer Mogul into Grand Prix racing.

Trouble erupts around Mogul's new North Sea rig when a few unguarded words open old wounds in a Tyneside shipyard.

The glittering world of advertising is a wonderful dream for Miss Mogul, Sandra Spratt. But others have a different view - and create a headache for Derek Prentice and Mogul.

Prejudice has deep roots. Driscoll is involved in an explosive situation in northern Canada when Mogul takes an Iroquois Indian for an important job.

Freedom is very desirable. But when Peter Thornton envies the life of a Mogul tanker driver he finds that no man is as free as he seems.

A beautiful girl and a heart attack combine to make Brian Stead want to retire. But attacks from within Mogul rouse his fighting instincts and complicate his decision.