Sherlock Season 4: 18 Easter Eggs & References From 'The Lying Detective'
4. Sherlock Has An Evil Sister?!
Yes, Sherlock has a sister. While it might come as a surprise to fans of Doyle's work and Sherlock, there are previous examples of the detective having a female sibling.
Most prominently, American author Nancy Springer wrote a series of young adult novels called The Enola Holmes Mysteries from 2006 to 2010. They starred Sherlock's teenage sister Enola, twenty years his junior, as she aims to follow in her big brother's shoes as a detective.
Likewise, Sherlock's other sibling has also been presented as evil on occasion. In 2010's straight-to-DVD movie Sir Arthur Conan Doyle's Sherlock Holmes, Sherlock has a brother called Thorpe who turns out to be the cad responsible for terrorising old London town with his army of robot dinosaurs (just go with it).
The reveal has also been hinted at within Sherlock itself. Back in the show's pilot A Study in Pink, Sherlock assumed that John's unseen sibling Harry was a male. Actually, it's his sister.