As in the Realm of Fire, Sigmar had sent a storm to launch a small force of Eternals into the Realm of Metal. Their first task was to capture the Silverway, a Realmgate that led back to their home in Azyr, the Realm of Heavens. Without the Silverway, more Stormcasts could not be sent to the Realm of Metal and the beachhead could easily be overturned by Chaos. So, capturing the Silverway was paramount, just as capturing the Gate of Azyr was in the Realm of Fire.
However, when the Stormcasts arrived, there was… nothing. No opposition at all. The Silverway had been found (after a bit of searching) in the ruins of a Duradin settlement, but there had been no fighting, much to the chagrin of Lord-Celestant Eldroc who was, frankly, up for a bit of smiting Chaos.
He did not have too much longer to wait, however, as a roiling wave of blue fire approached the Stormcasts, and within was the first wave of the Bleak Horde, powerful Chaos Warriors dedicated to Tzeentch.
Full report and more piccies here: link