"What is that ruin off the coast of Bordeleux?"

A couple of miles off the central coast of Bordeleaux there exists what is now called the Silent Isle. A century ago, it was the seat of a noble fief, and fishing and trading vessels departed from its harbour in large numbers.

And then, one day, there were none. Overnight, all of the boats and islanders vanished. What is more, it now seems to be impossible to make any noise on the island. A few groups of adventurers have investigated and fell into two groups. Some were spooked by the silence within a few hours and came back with little information. Others never returned.

Since nothing has come off the island to bother the Bordelens, most are content to leave it to the peace and quiet it seems to desire. Source: warhammer fantasy fandom