investigating—" "Oh, Bob, it is! I recognize his voice!" the girl screamed. "Quiet! This is a zwilnik outfit, isn't it?" "I'll say it is," Ryder gasped in relief. "Thionite—" "That's enough, details later. Keep still a minute!" Locked together in almost overpowering relief, the imprisoned pair listened as the crisp voice went on: "Lieutenant? I was right—zwilnik. Thionite! Get over here fast. Blast down the Mayner Street door—stairway on right, two flights down, corridor to left, half-way along left side, Room B twelve. Snap it up!" "But wait, Cloud, wait!" they heard a fainter voice protest. "Wait until we get there. You can't do anything alone!" "Can't wait. Got to get these kids out—evidence!" Cloud broke the circuit and, as rapidly as his one hand permitted, buckled gun-belts around himself. He knew that Graves would have to kill those two youngsters if he possibly could. If they were silenced, it was eminently possible that all other evidence could be destroyed in time. "For God's sake save Jackie anyway!" Ryder prayed. He knew just how high those stakes were. "And watch out for gas, radiations, and traps—a dozen alarms must have been sprung before now all around here." "What kind of traps?" Cloud demanded. "Deadfalls, sliding doors—I don't know what they haven't got in this damned place." "Take Fairchild's private elevator, Doctor!" the girl's clear voice broke in. "Graves said that he could kill us in here with gas or rays or—" "Where is it?" "The one farthest from the stairs." Cloud jumped up, listening with half an ear to the babblings from below as he searched for air-helmets. Radiations, in that metal-lined room, were out—except possibly for a few narrow-beam projectors, which he could deal with easily enough. Gas, however, was bad. They couldn't weld cover-plates everywhere, even if they had time and metal. Every drug house had air-helmets, though, and this one must have hundreds of them. Ah! here they were!