In Victorian London, Sherlock Holmes and Dr. John Watson attempt to solve a murder committed by a ghost bride.
While waiting for Moriarty to make good on his beyond-the-grave threat, Sherlock is intrigued by cases of vandalism where the criminal is breaking open busts of Margaret Thatcher. He soon discovers that the vandalism is tied to Mary's past.
To save John, Sherlock takes on the most dangerous case of his career: bring serial killer and milliionaire-philanthropist Culverton Smith to justice. Meanwhile, the mystery of Sherringford Holmes deepens.
Sherlock and John confirm that Eurus is still alive, and go to Sherringford to meet with her. However, they soon discover that it is all part of Eurus' master plan.
