When the BBC’s television series Sherlock debuted in summer 2010 and traveled to the U.S. via PBS a few months later, no one—including Hartswood Films producers, series co-creators Steven Moffat and Mark Gatiss, stars Benedict Cumberbatch (Sherlock Holmes) and Martin Freeman (John Watson), or those who would become ardent fans—knew what an international phenomenon it would become. Since then, Sherlock has encouraged a diverse fandom who participate in such traditional fan activities as writing fiction, creating art, attending conventions, and buying merchandise. Yet, Sherlock fandom does far more than that. Like the object of their affection, Sherlock Holmes, fans scrutinize clues about the series’ meaning and deduce what happens off screen or off the set, then share their findings across the internet. They postulate theories and create personally empowering readings of the characters and relationships. They have tweeted with The Powers That Be, mobilized to filming locations via #Setlock, and become advocates for LGBTQIA communities. Sherlock’s digital communities have changed the way that fans and TPTB interact in person and online as each publicly takes “ownership” of beloved television characters who represent far more than entertainment to their fans.