"Line up, men!" cried the leader of Frank's detachment, and the high state of discipline that the American forces had reached was shown by the promptness with which the order was obeyed. A signal was sent back to the supporting guns, and they opened up a deadly barrage fire over the heads of Frank and his comrades, clearing the ground before them of everything that dared to show itself in the open. Behind this curtain of fire, the boys advanced, slowly at first, but gathering speed at every stride, until they were running at the double quick. Bullets rained about them from the machine guns of the enemy and great shells tore gaps in the ranks. At Frank's left, a soldier suddenly wavered and then pitched headlong into a shell hole and lay still. Another toppled over with a bullet in his shoulder. But the lanes that were made closed almost instantly. Now they had reached the wire entanglements that had been battered by the artillery until they hung in festoons around their posts, leaving paths through which the American lads poured. Then like a great tidal wave they struck the trench! The Germans had clambered out to meet them, and when the two forces met the shock was terrific. Back and forth the battle surged and swayed, each side fighting with the fury of desperation. The cannon had ceased now, for in that locked mass the shells were as likely to kill friends as foes. It was man against man, bayonet against bayonet, each combatant obeying the primitive law of "kill or be killed." The opposing forces at this part of the line were nearly equal, with the Germans having a slight advantage in numbers. But to make up for this, the Americans had the advantage of the attack and the tremendous momentum with which they had struck the enemy's line. For a time victory hung in the balance, but then Yankee determination and superior skill in bayonet work began to tell. The Americans would not be denied. The German line was pierced, and the forces broke up into a number of battling groups. Frank and Bart, Billy and Tom, who all through the fight had managed to keep together, found themselves engaged with a squad of Germans double their number, two of whom were frantically trying to bring a machine gun to bear upon them. With a bound Frank was upon them. He toppled one over with his bayonet, but while he was doing this the other fired at him point-blank with a revolver. At such a close range he could not have missed, had not Bart, quick as a flash, clubbed him over the arm with his rifle, making the bullet go wild. "Quick, Bart!" panted Frank, as with his comrade's help he slued the machine gun around, gripped the trigger, and sent a stream of bullets into a group of the enemy charging down upon him. Before that withering fire they dissolved like mist, and a circle was cleared as though by magic. What Germans were left in that immediate vicinity leaped back into the trench on the edge of which they had been fighting.