Lord Alexander Archibald is a puppet of Intryzz. We have therefore two choices. Either, attempt to free him, a likely impossibility with Intryzz's reputation, or for another to take up the reins of the House. Namely, you, sir. With no Archibald left, you are the highest ranking member.
Take over the House and its resources, and let the organisation become House Crowshire. You've had enough experience running its day-to-day matters, so please, assume command, sir.
-Egon