The Alliance and the Horde clash in a series of running battles in Stonetalon Mountain, culminating in a desperate last stand by the Alliance on the island in Mirkfallon lake. (More information about this event can be found here.) Please note, this is a mildly fictionalised account of the event.

Escalation: Prelude to War

Although a strategic land-route to their southern holdings for the Kaldorei, and potential attack route on Crossroads for the Horde, Stonetalon Mountain has long been a backwater. That changed when rumours of Horde forces moving in strength through the area lead to the Silvereye gathering a small war party and moving south to reconnoitre in force. Anxious to prevent the Silvereye from "having all the fun on their own", the stalwart dwarves of the Clans Morogh gathered an Army of the Mountain, bolstered by a number of others, including the redoubtable mage Zalamar set out from Nijel's Point.

Meeting Engagements

The Horde presence in Stonetalon Mountain was stronger than reported. A powerful force moved north to block the Silvereye warparty at Windsheer Crag, while another Horde force skirmished with the Dwarves, before finally breaking their lines. On both fronts, the Alliance forces, equipped for speed and scouting, were met by battle-hardened Horde forces heavily armed and equipped from the bottomless armouries of Ogrimmar.

Forced Back

Withdrawing in the best order they could manage, the Alliance forces retreated to the island at the centre of Mirkfallon Lake - to regroup and regain the intiative. The Horde forces did not grant them much respite, coming on in wave after wave, intent on dislodging them from the Island.

   
The Alliance forces battered and battle-weary after a series of battles with the warriors of the Horde retreat to the island in the middle of Mirkfallon Lake for a desperate last stand.   The Horde, flushed with their victories in the initial skirmishing, gather their forces outside Sunrock Retreat prior to launching a final attack.   The Horde's warriors launch their final assault, foul magics striking terror into the stalwart defenders, and buying the Horde the instant they need to force their way onto the island.
       
After heavy fighting and grevious injuries, the humans, dwarves, gnomes and night-elves drove off the Horde assault.        

Aftermath

Though they had survived the assault, the Horde was brining up massive reinforcements, and the Alliance force had little choice but to break off and make for the Kaldorei outpost of Stonetalon Peak and fortify it against further assault by the Horde. For the time being, the Horde would be in control of Stonetalon Mountain, and on the offensive in the rising conflict in the region.