Sherlock is a British crime television series based on Sir Arthur Conan Doyle's Sherlock Holmes detective stories. Created by Steven Moffat and Mark Gatiss, it stars Benedict Cumberbatch as Sherlock Holmes and Martin Freeman as Doctor John Watson. 13 episodes have been produced, with four three-part series airing from 2010 to 2017, and a special episode that aired on 1 January 2016. The series is set in the present day, while the one-off special features a Victorian period fantasy resembling the original Holmes stories. Sherlock is produced by the British network BBC, along with Hartswood Films, with Moffat, Gatiss, Sue Vertue and Rebecca Eaton serving as executive producers. The series is supported by the American station WGBH-TV Boston for its Masterpiece anthology series on PBS, where it also airs in the United States. The series is primarily filmed in Cardiff, Wales, with North Gower Street in London used for exterior shots of Holmes and Watson's 221B Baker Street residence.
Sherlock depicts "consulting detective" Sherlock Holmes (Benedict Cumberbatch) solving various mysteries in modern-day London. Holmes is assisted by his flatmate and friend, Dr. John Watson (Martin Freeman), who has returned from military service in Afghanistan with the Royal Army Medical Corps. Although Metropolitan Police Service Detective Inspector Greg Lestrade (Rupert Graves) and others are suspicious of Holmes at first, over time, his exceptional intellect and bold powers of observation persuade them of his value. In part through Watson's blog documenting their adventures, Holmes becomes a reluctant celebrity with the press reporting on his cases and eccentric personal life. Both ordinary people and the British government ask for his help.