Concealed in the louvres of the air-conditioner intake of the lower building was a specially constructed suit and several hundred feet of power line which was connected to the main line of the building.
In the darkness, Houston slipped on the suit. It was constructed somewhat like a light diving suit or a spacesuit, but without the helmet. In the toes, knees, and hands, were powerful electromagnets controlled by switches in the fingers of the gloves and powered by the current in the long line.
Houston stepped over to the blue aluminum wall, reached out a hand, and lowered one finger. Instantly, the powerful magnet anchored his hand to the wall, held by the dense magnetic field to the steel beam beneath the aluminum sheath. That one magnet alone could support his full body weight, and he had six magnets to work with.
Slowly, carefully, David Houston began to crawl up the wall.
Turn on a magnet in the right hand; lift up the left hand and anchor it higher; turn on the right hand and lift it even with the left, then anchor it again; do the same with both legs; then begin the process all over again, turning the magnets off and on in rotation.
Up and up he went. Past the forty-sixth floor, past the forty-seventh, the forty-eighth, and the forty-ninth. Not until he reached the fiftieth floor did he attempt to open one of the windows.
There was a magnetic lock inside the window, but Houston had taken that, too, into account. The powerful magnet in his right glove slid it aside easily. Houston lifted the window and stepped inside.
He had ten more floors to go.
He took off the suit and rolled it up into a tight package, then dropped it out the window. It landed with a barely audible thump. Houston took a deep breath, drew his stun gun, and headed for the stairway.