Just how the Germans progressed so fast that by noon on October 24 they had a machine-gun posted on the square in Caporetto still remains, eight days later, incompletely explained.  All that is really known is this:  at 2 a.m. they started a very violent bombardment.  When the shelling suddenly stopped after only two hours, the Italians regarded the interruption merely as a lull, for the artillery preparation for an infantry attack in force usually lasts much longer.  With the valley hidden by darkness, mist, and rain, and seeing more dimly than usual through the mica of their gas-masks, the Italians knew nothing of the German infantry’s advance up the valley from the Santa Lucia bridgehead, south of Tolmino, until the enemy had actually reached their wire.  In this way the Plec line of defense across that reach of the Isonzo known as the Conca di Plezzo, a line specially designed to check an offensive from Santa Lucia, was captured by surprise, and then German troops poured down into the river gorge from Mrzli on its eastern side, until the valley was full of the enemy, and Monte Nero and the other Italian outpost positions on the heights beyond the Isonzo were completely surrounded.

[Sidenote:  Violent fighting on the Bainsizza plateau.]

The valley being in their possession, the Germans wasted no time.  Pushing northward along the river, one detachment occupied Idersko and Caporetto; another proceeded to assault the height of Starijok, just above Caporetto; yet another strong force made a frontal attack on the ridge of Zagradan, which runs like a wall along the Italian side of the river, and after fierce fighting took Luico, one of the pivots of the defenses upon it.  Elsewhere he had attacked at the same time with less definite result.  Mount Globocak was seized by surprise.  It was an Italian big-gun position, and orders were given for it to be retaken at any cost.  So a distinguished brigade of bersaglieri was sent up to counter-attack, and drove the Germans from the captured guns down the slopes of Globocak again.  North of Caporetto, too, the angle of the Italian line at Zaga had been assailed, but had resisted, and across the river on the Bainsizza plateau the most violent fighting of all took place, as a result of which the Italian line was withdrawn from Kal, and the heavy guns and equipment were sent back across the Isonzo, though the Italian counter-attacks on the Bainsizza were carried out with such dash that they captured several hundred Austrian prisoners.

[Sidenote:  Danger that the Italian Army may be trapped.]

Now the enemy’s plan stood out in all its formidable strength and strategy.  He had opened a gap in the Italian front; through this gap he was pouring overwhelming forces.  Already the rest of the Italian Second Army and the Third Army on the Carso to the south of it were outflanked.  If the whole of that great force was not to have its line of communications cut and be surrounded, it must be immediately and rapidly withdrawn for a great distance.  An immense sacrifice of Italian territory was imperative if the Italian Army was to be saved from a trap by the side of which the fall of Metz was the capture of an outpost.  During the afternoon of October 25 the general order of retreat was given.