Sherlock: 7 Things We Can Look Forward To In Season 4

5. Another Holmes Brother?

Near the end of His Last Vow, when Mycroft is discussing what to do with Sherlock, he says: "I am not given to outbursts of brotherly compassion. You know what happened to the other one." There's another Holmes brother? Who is he? What happened to him? Is he even canon? Well, no, not really. The only mention of another Holmes brother is in William S. Baring-Gould's 'Sherlock Holmes of Baker Street,' where Sherrinford Holmes is described as the eldest of the three Holmes brothers, with apparently even stronger deduction skills than Mycroft or Sherlock. The name "Sherrinford" is taken from one of the options Conan Doyle considered for his detective before settling on the name "Sherlock." In a show where even the smallest detail is intentional, I don't believe that this is just a throw-away line. If they bothered to mention the character, it's quite possible that this mention is foreshadowing for next season. I can't even imagine what a person who is even more socially disinclined than Sherlock or Mycroft would be like. Perhaps we'll find out what happened to him, and how Mycroft was involved. In any case, it's an intriguing idea to explore.