The official Rolls-Royce carrying J toward the Tower of London was not quite like the advertisements-so quiet that all he could hear was the ticking of the electric clock. But it was almost that quiet, and otherwise there were only faint traffic noises outside. It was eleven o'clock on a spring night, and London was either going to sleep or already asleep.

J would normally have been in bed and asleep also. Part of his rise to the position of head of the special intelligence branch MI6 was the result of years of rising early, not only before the dawn but before his rivals (and his enemies). But tonight Richard Blade was being hurled through Lord Leighton's gigantic computer on his ninth journey into Dimension X. J would sooner have violated the Official Secrets Act than not be on hand when his best agent-almost like a son to him was hurled off into some fantastic other world to live or die by his own quick wits and superb physical prowess.

Blade had made the same journey eight times. The first time it had been by accident, when an experiment indirectly linking one of Lord Leighton's earlier computers to Blade's mind has gone spectacularly awry. The remaining times, however, his journeys had been part of a deliberately contrived project to explore what was now called Dimension X, for the benefit of England. Over the short time of its existence, Project Dimension X had grown from a bee in Lord Leighton's white-haired bonnet to a massive undertaking housed in a self-contained complex more than two hundred feet below the Tower. Its financing swallowed money to the tune of better than half a million pounds a year. It drew on the talents of some thirty of England's most brilliant men-scientists, engineers, psychologists-without letting them know what they were serving. Only four people in the whole world-J hoped-knew full details. Blade, Lord Leighton, the Prime Minister, and J himself.