They were identical.

Woolford looked up. "Counterfeit. Which one is the bad one?"

"That is exactly what we would like to know," the Boss said.

Larry Woolford stared at his superior, blinked and then examined the bills
again. "A beautiful job," he said, "but what's it got to do with us, sir?
This is Secret Service jurisdiction, counterfeiting."

"They called us in on it. They think it might have international
ramifications."

Now they were getting somewhere. Larry Woolford put the two bills on the
Boss' desk and leaned back in his chair, waiting.

His superior said, "Remember the Nazis turning out American and British
banknotes during the Second War?"

"I was just a kid."

"I thought you might have read about it. At any rate, obviously a
government--with all its resources--could counterfeit perfectly any currency
in the world. It would have the skills, the equipment, the funds to
accomplish the task. The Germans turned out hundreds of millions of
dollars and pounds with the idea of confounding the Allied financial
basics."

"And why didn't it work?"

"The difficulty of getting it into circulation, for one thing. However,
they did actually use a quantity. For a time our people were so alarmed
that they wouldn't allow any bills to come into this country from Mexico
except two-dollar denomination--the one denomination the Germans hadn't
bothered to duplicate. Oh, they had the Secret Service in a dither for a
time."

Woolford was frowning. "What's this got to do with our current situation?"

The Boss said, "It is only a conjecture. One of those bills is counterfeit
but such an excellent reproduction that the skill involved is beyond the
resources of any known counterfeiter. Secret Service wants to know if it
might be coming from abroad, and, if so, from where. If it's a
governmental project, particularly a Soviet Complex one, then it comes
into the ken of our particular cloak-and-dagger department."

"Yes, sir." Woolford said. He got up and examined the two bills again.
"How'd they ever detect that one was bad?"

"Pure fortune. A bank clerk with an all but eidetic memory was going
through a batch of fifties. It's not too commonly used a denomination, you
know. Coincidence was involved since in that same sheaf the serial number
was duplicated."

"And then?"

"The reproduction was so perfect that Secret Service was in an immediate
uproar. Short of the Nazi effort, there has never been anything like it.