Albert immediately goes to the Count's house to throw down, as it were.
But the Count is having alone time and won't be bothered. His servant tells Albert that the Count will be at the opera that night.
Albert tells Lucien Debray, Franz, and Maximilian to meet him at the opera that night too.
Later that day, Mercédès tries to calm her son down, to keep him from doing anything crazy. Albert tries to figure out if she knows why the Count would want to ruin her husband.
At the opera that night, Albert bursts into the Count's private box and challenges him to duel. Like the civilized gentlemen that they are, they set the time of the duel for eight o'clock the following morning.
The Count asks Max and Emmanuel (Max's sister's husband) to be his assistants and moral support at the duel.