Determined to keep Amelia out of harm's way, Holmes sends her back to the relative safety of undercover work. While Holmes searches for answers about the missing jewels, Amelia learns that in this society, the most dangerous place for a lady may just be a debutante ball.

The game is afoot! Having cracked the code of the Red Thread's communications network, Sherlock, Amelia, and their friends are hot on the path of the kidnap victims, chasing a trail of breadcrumbs that leads all the way to the vaults of the Bank of England.