McColla returned soon after the battle at Fyvie with a battle plan that Montrose regarded as impossible. McColla had raised a formidable body of Scottish Highlanders, all of whom felt a desire to completely crush the Campbell Clan. They were predominantly Macdonald allies like the Clan Ranald. McColla proposed a raid through the heartland of Campbell-owned estates, in effect the complete destruction of Argyllshire. The assault was to culminate in a near suicidal march on Argyll's personal estate at Inverlochy, which was thought impossible to capture. The march on Inverlochy was made, despite Montrose's reservations, though he accompanied the force. Argyllshire was indeed razed. The hundreds of square miles covered were more remarkable for the season-during the winter blizzards of early 1645, when the sea off the coast froze. The culminating attack, and massacre of Campbells at Inverlochy on 2 February 1645 was made after a two-day march over the foothills of Ben Nevis. Argyll abandoned his men and sailed away on his personal galley to save himself.