Nearer and nearer came the boat. They listened in vain for the second craft. It was evident that it was either far behind or perhaps had been left at the mouth of the tunnel to trap them when they should try to emerge.
Closer, still closer the boat came, and the Army Boys lay like so many statues, holding their breath lest the slightest sound should betray them.
Now they knew that the boat was almost abreast, as they could hear the labored breathing of the men tugging at the oars.
But just then the leader of the Huns turned a flashlight in their direction, revealing the four figures. There was a shout, a sharp command in guttural tones, a dropping of oars and a click of rifles as the men raised them to their shoulders.
But quick as they were, Frank was quicker.
Lithe as a panther, he sprang to his feet and hurled the grenade that he had been holding in his hand full at the boat.
There was a blinding flash, a terrific explosion and the air was filled with flying bodies and debris. Frank himself was thrown to the ground by the shock, but scrambled to his feet again, none the worse except for a few bruises.
It was too dark to see the effects of the explosion, but the dead silence that followed told its own story. There was nothing more to be feared from that special group of enemies.
His own comrades gathered around Frank, themselves too dazed and shaken by the suddenness of the whole affair to understand fully just what had happened.
“What did it?” asked Billy.