Colonel Welsh didn’t reply for a couple of minutes. He seemed to go off into a thought trance. He stared at Dave and Freddy, and also right through them. He played with the gashed copper disc with his right hand, and continually clenched and unclenched his left fist.

“Yes, it’s all right for you to ask,” he finally said in a gloomy voice, “but there’s blessed little I can tell you about him. At least, blessed little that’s definite and concrete. Back in Washington my biggest Axis agent file happens to be on this Seven-Eleven. But if you want to know the truth, I have a hunch I could throw the whole confounded thing into the ash can, and I wouldn’t lose a thing of real value. In a few words, Seven-Eleven is Mystery Man Number One. He is Mystery Man X. And for the past couple of months he has been the biggest and sharpest thorn in the side of U.S. Intelligence. And for all I know right now, this Seven-Eleven may be a dozen persons, and not just one.”

Colonel Welsh paused for breath, and fell to playing with the gashed copper disc again.

“Seven-Eleven,” he continued eventually, “is only the name we’ve tacked on him. If you play dice you know that seven and eleven are the two lucky numbers. So we call him Seven-Eleven because he seems to have double luck in every single thing he does. In my file I have a report that states he was born in Germany under the name of Karl Bletz. That he came to this country shortly after the last war, and became a naturalized citizen under the name of Paul Benz. The report goes on to state that he returned to Germany in 1933 and hooked up with Hitler’s movement. He’s been back here several times, but the last time he was here was in 1938. He went back for good then, and went out to South America to boost German trade there, but actually to do Gestapo work that would estrange the South American countries from the United States. He made out all right on that job, particularly in Argentina and Chile.”

The senior officer paused again, shrugged, and then continued with his story.

“Since then he has been like a lighted fuse ready to touch off anything that would hurt England’s cause, and ours. Cargos arriving from U.S. ports have mysteriously burned up on South American docks. And our ship owners have had to take the loss. Many England-bound ships leaving South America never arrived. In fact, they were never heard of again. And lately, many of our own ships have gone down, and crew members drowned, because of him. I even have a report that he was at Pearl Harbor on that back-stabbing day of December Seventh. We feel sure that certain mysterious munition plant explosions in the U.S. were planned and carried out by his sub-agents. He—”

Colonel Welsh stopped short, gestured slightly, and dragged down both corners of his mouth.

“I realize that all this may sound just a little on the fantastic side,” he said. “How could we possibly tell that he had a hand in all these things? Well, simply the way police forces can tell that a certain known criminal had a hand in several robberies, or murders, or what have you. The man’s mark. His trademark, you can call it. A definite little touch to each crime that tags it as having been committed by the same man. Well, we’ve run into that same thing with this unknown, Seven-Eleven, as we call him. A couple of things here and there that are identical with things discovered at other mysterious explosions, and so forth.

“In other words, there is one man behind most of the Nazi spy doings in the U.S., and Central and South America. He is the cleverest agent ever to come from Berlin, and the luckiest. But he is also the most deadly. Get in his way, and you’re a dead man. I’m sure he’d slay his own mother if it would help him any. But this I do know! Twelve of my crack agents, stretching from the Canadian border to the bottom tip of the Argentine, have been after him for months trying to trip him up, and catch him.”

Colonel Welsh cut off his words with a harsh sound, and there was the glitter of highly polished steel in his eyes.