ent. She hung
up her coat. "I am sorry. I stopped at a store."

He had paused in his pacing to nod at her. Now he stared, but her back
was turned toward him. He blinked. She had just told a very transparent
lie. And Helena was normally very truthful.

"You had a good trip?" she asked politely.

"Fair," said Coburn. "Any phone calls this morning?" he asked.

"Not this morning," she said politely.

She reached in a desk drawer. She brought out paper. She put it in the
typewriter and began to type.

Coburn felt very queer. Then he saw something else. There was a fly in
the office--a large, green-bodied fly of metallic lustre. The
inhabitants of Salonika said with morbid pride that it was a specialty
of the town, with the most painful of all known fly stings. And Helena
abhorred flies.

It landed on the bare skin of her neck. She did not notice. It stayed
there. Ordinarily she would have jumped up, exclaiming angrily in Greek,
and then she would have pursued the fly vengefully with a folded
newspaper until she killed it. But now she ignored it.

Hallen came in, stamping. Coburn closed the door behind him. He felt
queer at the pit of his stomach. For Helena to let a fly stay on her
neck suggested that her skin was ... somehow not like its usual self.

"What happened to those Bulgarians?" demanded Hallen.

Coburn told him precisely what he'd seen when he arrived in Naousa after
an eight-mile hike through mountains. Then he went back and told Hallen
precisely what he'd seen up on the cliffside.

"His cameras were some sort of weapon. He played it on the marching
column, it took effect and they went to sleep," he finished. "I took
them away from him and brought them down, but--"

He told about the contents of the camera cases being turned to a gritty,
sooty powder. Then he added: "Dillon set them to destroy themselves. You
understand. He's not a man. He's a creature from some planet other than
Earth, passing for a human being. He's an Invader from space."

Hallen's expression was uneasy and compassionate but utterly
unbelieving. Helena shivered and turned away her face. Coburn's lips
went taut. He reached down to his desk. He made a sudden, abrupt
gesture. Hallen caught his breath and started up.

* * * * *

Coburn said curtly: "Another one of them. Helena, is that foam-suit
comfortable?"

The girl jerked her face around. She looked frightened.

"Helena," said Coburn, "the rea