Suddenly Inspector Campbell stumbled on the slippery rock floor and went down in a heap. Instantly Chandra Dass and his two followers recoiled from them, the two pistols trained on the detective as he scrambled up.
"Do not do that again, inspector," warned the Hindoo in a deadly voice. "All tricks are useless now."
"I couldn't help slipping on this wet floor," complained Inspector Campbell.
"The next time you make a wrong step of any kind, a bullet will smash your spine," Chandra Dass told him. "Quick—march!"
The tunnel turned sharply, turned again. As they rounded the turns, Ennis saw with a sudden electric thrill of hope that Campbell held clutched in his hand, concealed by his sleeve, the heel-hilted knife from his shoe. He had drawn it when he stumbled.
Campbell edged a little closer to the young American as they were hastening onward, and whispered to him, a word at a time.
"Be—ready—to jump—them——"
"But they'll shoot, your first move——" whispered Ennis agonizedly.
Campbell did not answer. But Ennis sensed the detective's body tautening.