Blade had been on his way back to London when the MG gave out. In London he would sit down in a room carved out of the rock far below the Tower of London. His brain would be electronically linked to the giant computer that filled most of the room. Then the computer's inventor Lord Leighton would pull a red switch and the pulses from that computer would flow into Blade's brain. The room, the computer, Lord Leighton, everything Blade saw with his normal senses would vanish. He would whirl off into nothingness, and awake somewhere in the vast unknown they called Dimension X.

Blade was the only living human being who could travel into Dimension X and return alive and sane. He was about the most perfect combination of physical and mental qualities anyone could imagine-as long as he was in good health. If he succeeded in getting himself thoroughly battered and banged about in an ordinary train wreck, the trip to Dimension X would be off until he was fully recovered. Even Lord Leighton would have to admit that, though he would do so with the worst possible grace. Lord Leighton had the finest scientific mind in Britain and one of the worst tempers in the world.

There was also the man called J. He was one of the greatest of living spymasters, the head of the secret intelligence agency MI6, the man who saw Blade's promise while the younger man was still at Oxford. Under J's guidance Blade became one of the top agents for MI6. But to J he was also the son the older man had never had. J would be worried about Blade's accident, even though his worrying would be hidden from everyone-except Blade-behind a sober, reserved mask.

All that was for tomorrow. For the moment, Blade's job was doing what he could for the other passengers on the wrecked train. The mother and her little girl were stiff with fright, but Blade couldn't see any visible injuries. Then the child opened her mouth and started bawling lustily. Blade could hardly believe any child able to make that much noise could be seriously hurt. The mother's eyes met his and she smiled sheepishly.