Vikner's diabolical maneuvering to secure his position becomes known. Sherlock concocts a plan to unseat him only to unwittingly enable a power struggle the ends of which he could barely have believed possible.
Holmes and Watson's lives are threatened by an influential, worldwide criminal network connected to the murder attempt on Morland Holmes (John Noble). Also, Sherlock's grievances with his father threaten their alliance to bring their mutual adversary to justice.