"A Study in Pink" is the first episode of the television series Sherlock and first broadcast on BBC One and BBC HD on 25 July 2010. It introduces the main characters and resolves a murder mystery. It is loosely based upon the first Sherlock Holmes novel, A Study in Scarlet.
The episode was written by Steven Moffat, who co-created the series. It was originally filmed as a 60-minute pilot for Sherlock, directed by Coky Giedroyc. However, the BBC decided not to transmit the pilot, but instead commissioned a series of three 90-minute episodes. The story was refilmed, this time directed by Paul McGuigan. The British Board of Film Classification has rated the pilot as a 12 certificate (not suitable for children under 12) for video and online exhibition, and it is included as an additional feature on the DVD released on 30 August 2010.
Plot
John Watson, an army doctor injured in Afghanistan, meets Sherlock Holmes, who is looking for a flatmate to share a flat at 221B Baker Street, owned by landlady Mrs. Hudson. The police, led by Detective Inspector Lestrade, have been baffled by a series of deaths, described as "serial suicides". Holmes looks at the latest crime scene: the body of Jennifer Wilson, who was dressed in pink. She managed to claw the word "Rache" into the floor, and Sherlock determines that the victim died before completing the name "Rachel", which later turns out to be the name of her deceased daughter. Holmes deduces she is from out of town and therefore had a suitcase. The police have not found a carry-on with the body, but Holmes discovers it abandoned nearby. Meanwhile, after a phone call, Watson is compelled to meet a man who claims to be Holmes's "arch-enemy". The man offers him money to spy on Holmes, but Watson refuses. He also tells Watson that, contrary to what his therapist believes, he is not suffering from post-traumatic stress disorder, but in fact misses being in combat.
When Watson returns to Baker Street, Holmes asks him to text Wilson's still-missing phone, hoping the murderer will make a move. While waiting at a local restaurant, Holmes notices a taxi and they outpace it on foot with shortcuts. However, the passenger is innocent. Holmes presumes "Rachel" was Wilson's e-mail password, and the victim planted her phone on the killer so that he could be traced by GPS. At the same time, Watson finds the signal is coming from 221B Baker Street; Mrs. Hudson tells Holmes a taxi is waiting for him. Outside, the cabbie confesses to the murders but proclaims he merely speaks to his victims, and they kill themselves. The cabbie challenges Holmes to solve his puzzle. Later, he pulls out two bottles containing an identical-looking pill: one is harmless, the other is poison. Afterward, he invites the victims to choose one, promising he will swallow the other — and he threatens to shoot them if they refuse.
Sherlock soon deduces the driver is an estranged father who was told three years earlier he was dying. The driver admits that he has a "sponsor" for his work, paying money for each murder for the driver's children. Holmes, having already noticed that the 'gun' is a novelty cigarette lighter, attempts to leave. However, the driver re-challenges him to choose a pill and see if he can solve the puzzle. Meanwhile, Watson has traced the GPS signal from the phone and followed the two men. He shoots the driver through a window in the adjacent building. Holmes tortures the cabbie to force him to say whether the pill taken was correct and who the sponsor is. While not revealing the truth about the pills, he eventually reveals the name "Moriarty". The police arrive, and Holmes deduces the shooter is Watson, but hides the truth from the police. Holmes and Watson leave the scene, encountering the enigmatic "arch-enemy" of Sherlock. He turns out to be Sherlock's elder brother, Mycroft, who works for the British government. Watson finally understands that Mycroft tried to bribe him out of genuine concern for Sherlock. Mycroft instructs his secretary to increase their surveillance status.