Periodically throughout Waterdeep’s history, the byzantine factions of the city—or some significant subset thereof—will become collectively fixated upon some single objective.
Thus will begin a Grand Game.
Unlike The Noble Game, which is limited to the inner machinations of Waterdeep's noble families, Grand Games run beyond the scope of simple high society squabbling. Though some of a given Game's players will be noble houses or members thereof, others will be members of powerful factions with a strong presence in Waterdeep, small bands of adventurers, and even particularly canny individuals.
Sometimes the goal of a Grand Game will be arcane. Often it is clandestine, although quite public struggles are not unknown; On no less than three occasions the Grand Game has revolved around the appointment of the Open Lord. Whatever the case, the intense rivalries of the Grand Game give birth to all forms of subterfuge, covert activities, deception, and intrigue.