Galloway being restored to order, Archie Forbes returned home, and remained for two or three months with his wife and mother.  He was then summoned by the king to join him again, as he was about to march to reduce the region over which his deadly foes Alexander and John of Lorne held sway.  The country into which the royal army now penetrated was extremely mountainous and difficult, but they made their way as far as the head of Loch Awe, where Alexander and John of Lorne, with 2000 men, were gathered to dispute the passage.  The position was an extremely strong one, and the Lornes were confident that it could not be forced.  Immediately to the north of the head of the lake rises the steep and lofty mountain Ben Gruachan.  From the head of the lake flows the river Awe connecting it with Loch Etive, and the level space between the foot of the mountain and the river is only wide enough for two to ride abreast.  This passage was known as the Pass of Brander, and the Lornes might well believe that their position was unassailable.

Before advancing into the pass Bruce detached Douglas, with Sir Alexander Frazer, Sir William Wiseman, and Sir Andrew Grey, with a body of lightly armed infantry and archers.  These, unnoticed by the enemy, climbed the side of the mountain, and going far up it, passed along until they got behind and above the enemy.  The king ordered his main body to lay aside all defensive armour so that they could more easily climb the hill and come to a hand to hand conflict with the enemy.  Then he moved along towards the narrow pass.  As they approached it the men of Lorne hurled down a torrent of rocks from the hillside above.

With a few heavy armed men Bruce pushed forward by the water side, while Archie Forbes led the main body up the hillside.  The climb was stiff and difficult, and many were swept down by the rocks hurled by the enemy; but at last they came to close quarters with the foe, and a desperate struggle ensued.

In the meantime Douglas and his party had attacked the defenders from the other side, at first showering arrows among them, and then falling upon them with sword and battleaxe.  Thus attacked in front and rear, the men of Lorne lost heart and gave way.  On both sides the royalists pressed them hotly, and at last they broke from the hillside and fled down to the river, intending to cross by a wooden bridge and destroy it behind them, but before many had passed Douglas with his followers arrived upon the spot and seized the bridge, cutting off their retreat.  Great numbers of the men of Lorne were slain, and the survivors made their escape up the mountain side again.  The Lornes themselves were on board some galleys on Loch Awe, their intention having been to land in Bruce’s rear when he was fairly entangled in the narrow pass.  On witnessing the utter discomfiture of their followers they rowed rapidly away, and landed far down the lake.  Alexander fled to England, where he ended his life.