The Peiping Explosion, back in the sixties, had almost started World War Three. An atomic blast had leveled a hundred square miles of the city and started fires that had taken weeks to extinguish. Soviet Russia had roared in its great bear voice that the Western Powers had attacked, and was apparently on the verge of coming to the defense of its Asian comrade when the Chinese government had said irritatedly that there had been no attack, that traitorous and counterrevolutionary Chinese agents of Formosa had sabotaged an atomic plant, nothing more, and that the honorable comrades of Russia would be wise not to set off anything that would destroy civilization. The Russian Bear grumbled and sheathed its claws. The vast intelligence system of the United States had reported that (A) the explosion had been caused by carelessness, not sabotage, but the Chinese had had to save face, and (B) the Soviet Union had no intention of actually starting an atomic war at that time. If she had, she would have shot first and made excuses afterwards. But she _had_ hoped to make good propaganda usage of the blast. The Peiping Explosion had caused widespread death and destruction, yes; but it had also ended up being the fastest slum-clearance project on record. The rebuilding had taken somewhat more time than the clearing had taken, but the results had been a new Peiping--a modern city in every respect. And nowhere else on Earth was there one hundred square miles of _completely_ modern city. Alteration takes longer than starting from scratch if the techniques are available; there isn't so much dead wood to clear away. In the middle of the city, the Chinese government had built its equivalent of the Kremlin--nearly a third of a square mile of ultra-modern buildings designed to house every function of the Communist Government of China. It had taken slave labor to do the job, but the job had been done. A little more than half a mile on a side, the area was surrounded by a wall that had been designed after the Great Wall of China. It stood twenty-five feet high and looked very quaint and picturesque. And somewhere inside it James Ch'ien, American-born physicist, was being held prisoner. Spencer Candron, alias Mr. Ying Lee, had to get him out. Dr. Ch'ien was important. The government of the United States knew he was important, but they did not yet know _how_ important he was. * * * * * Man had already reached the Moon and returned. The Martian expedition had landed safely, but had not yet returned. No one had heard from the Venusian expedition, and it was presumed lost. But the Moon was being jointly claimed by Russian and American suits at the United Nations, while the United Nations itself was trying to establish a claim. The Martian expedition was American, but a Russian ship was due to land in two months. The lost Venusian expedition had been Russian, and the United States was ready to send a ship there.