"Still romantic," he told himself satirically. "Even ten years of Asia hasn't ground all that out of you."

Shan Kar was telling Tark, "Lead the way. But, Tark, remember that if you try to go too fast you will die very quickly."

The wolf made no reply but trotted deliberately forward up the gently slanting tunnel. The three men, stooping, followed. Soon, the tunnel forked. Tark unhesitatingly took the left turn. They followed, their pistols and the light covering him.

The tense silent progress into these ramifying tube-ways beneath Vruun began to get on Eric Nelson's nerves. He began to think he could hear a whispering echo of sound from behind them.

He told himself as he glanced swiftly backward, that he was letting his nerve slip, that he-

He did glimpse something back there in the tunnel! Blazing eyes in the gloom, eyes that were following them!

"It's a trap! We're being followed-" Nelson started to yell.

But the wolf caught his thought and acted even as the sound left his lips. Tark whirled and charged back on them with inconceivable swiftness. His hairy body was a living battering-ram that knocked the little light from Nelson's hand. The wolf crashed on through them.

"Knew it!" shrilled Lefty Wister, and triggered his automatic half-blindly as the light smashed out against the floor.

The thunderous echoes of the forty-five were deafening in the confined tunnel and Nelson heard ricochets screaming. Then Tark, who had crashed back through them to join those other eyes following them, sent his thought through the dark to them.