When Elkinson's memory seems to be failing him, it is more than his personal happiness that is at stake - the lives of his passengers could be endangered. His problem soon becomes one for the air security officers.

In tonight's episode, the pilot of a plane bringing the president of a Middle Eastern state to London. But during the flight it is discovered that one of the tyres has been tampered with - and the plane will explode on landing. Jimmy Delaney, Garnett's American assistant accompanying the president, has to make a decision that may well cost the lives of all on board.

On a flight from Montreal, young Mrs Clandon dies, apparently of heart failure, another passenger, the elderly Mrs Pendenny accuses Mr Clandon of murdering his wife. Obviously her charges must be investigated - but Mrs Pendenny is known by her friends, among them Mrs Trapp, to be an incorrigible liar …