boy will
never know the difference_.

He walked right on up to the doorway, pretending not to notice
Brittain. Evidently, the saboteur was a little flustered, not quite
knowing who Karnes was. He, too, pretended that he had no suspicions.
He pressed a buzzer on the panel to announce himself to a guest.
Karnes noticed it was 523; a fifth floor button.

The front door, inside the foyer, was one of those gadgets with an
electric lock that doesn't open unless you either have a key to the
building or can get a friend who lives there to let you in.

When Karnes saw Brittain press the buzzer, he waited a second and took
a chance.

"Here," he said, fishing in his pocket, "I'll let you in." _That ought
to give him the impression I live here._

Brittain smiled fetchingly. "Thanks, but I--"

Bzzzz! The old-fashioned lock announced that it was open. Karnes
stopped fishing and opened the door, letting Brittain follow him in.
He stayed in the lead to the elevator, and pushed the button marked
"4."

"You getting off before four?" he asked conversationally.

"No."

The elevator slid on up to four without another word being said by
either man.

Karnes was judging the speed of the elevator, estimating the time it
took for the doors to open as they did so, and making quick mental
comparisons with his own ability to climb stairs at a run. The
elevator was an old one, and fairly slow--

When the doors slid open, he stepped out and began to walk easily down
the hall toward the stairway. When the elevator clicked shut, he broke
into a run and hit the stairway at top speed, his long legs taking the
steps three at a time.

The stairway was poorly lit, since it was hardly ever used, and, at
the fifth floor, he was able to conceal himself in the darkness as
Brittain turned up the hall toward 523.

Karnes looked closely at his surroundings for the first time. There
was a well-worn, but not ragged, nylon carpet on the floor, dull
chrome railing on the stair bannisters, and the halls were lit by
old-fashioned glo-plates in the ceiling. The place was inexpensive,
but not cheap.

Having made sure that Brittain actually had entered 523, he stepped
back toward the elevator in order to notify Lansberg.

A sudden voice said: "You lookin' for-a somebody, meester?"

Karnes turned. An elderly man with a heavy mustache and a heavy body
stood partway up the stairs, clad in slacks and shirt.

"Who are you?" frowned Karnes.

"I'm Amati,