While power grabs are being made at the firm, Alicia and Caitlin square off against old foe Nancy Crozier (Guest Star Mamie Gummer). Meanwhile, Peter discovers the price of taking the moral high road.
Tensions rise when Holmes and Watson are forced to partner with Gareth Lestrade, Sherlock's former Scotland Yard colleague, on a bombing investigation. Sean Pertwee guest stars as Gareth Lestrade.