A phone call to Moriarty interrupts the standoff between him and Sherlock. Following the call, Moriarty leave Sherlock and John alive. Sherlock becomes a minor celebrity after John blogs about their activities. While investigating a case, Sherlock and John are brought before Mycroft (Mark Gatiss) in Buckingham Palace. He reveals that Irene Adler (Lara Pulver), a dominatrix known professionally as "the Woman", took compromising photographs of herself and a female member of the royal family. They want the pair to retrieve Adler's smartphone. Sherlock and John try get into Adler's home. However Adler has been expecting them and appears to them completely naked, leaving Sherlock unable to deduce anything about her, but through a false fire alarm, he finds her hidden safe. Several CIA operatives led by Nielson (Todd Boyce) break into the house and demand that Sherlock opens the safe. After realising the combination is Adler's measurements, he does so. The booby-trap in the safe kills one of the assailants. They disarm the agents. Adler then sedates Sherlock, takes the phone, and escapes.
Six months later, Sherlock learns via text that Adler has sent him her phone, which requires an unknown password, and realises she will be found dead; her mutilated body is later found and identified. Some time later, an intermediary contacts John and takes him to Battersea Power Station. John is surprised to find Adler, who faked her death to shake off her pursuers. Sherlock, having followed John, learns of Adler's survival. Sherlock returns home to find Nielson's team holding his landlady Mrs. Hudson (Una Stubbs) hostage. Sherlock throws Nielson out a window in revenge. Later on, Adler reveals that she is still being hunted and asks Sherlock to decipher a code stolen from an MOD official. He effortlessly cracks the code, revealing it to be an airline seat allocation number. Adler secretly texts the flight information to Moriarty, who in turn texts Mycroft, revealing that he is now aware of the MOD ploy to fool the terrorists trying to bomb a plane.
A government official brings Sherlock to Heathrow. He recalls the Coventry Blitz and suspects that something similar is happening. Mycroft confirms this: the US and UK governments have decided to fly an unmanned plane full of corpses so as not to alert the terrorists while avoiding casualties. However, as Sherlock unwittingly helped Adler and Moriarty crack the code, the scheme was foiled. Adler reveals a list of demands to Mycroft, including protection, in exchange for the release of the contents of her phone. Adler taunts Sherlock, saying that he meant nothing to her. However, Sherlock realises that she is intensely attracted to him, as he previously noticed her elevated pulse and her pupil dilation. He finally figures out the password and unlocks the phone with the word "SHER", so that its screen reads "I AM SHER-LOCKED". With her leverage gone, Adler pleads for protection, but Sherlock and Mycroft turn her down.
Some months later, Mycroft informs John that Adler has been beheaded by terrorists in Karachi, Pakistan, but asks him to tell Sherlock instead that she has entered a witness protection program in America. Sherlock appears to accept this and ask for Adler's phone. After John leaves, Sherlock reminisces his journey to Pakistan where he actually rescued her.
