The episode begins with Holmes giving Irene a hug. Cut to a little over two years ago, in London, Holmes meets Irene for the first time. He asks her if she read his email. She tells him to tell his friend, Mr. Kirby, at the Christy’s that the canvases that turned up are not original. She explains why. Holmes looks around and asks that Irene, who is a restorer, as to why she has kept an original painting with her and sold her work to the museum. He notices there are a couple of original paintings that Irene has kept with her or rather stolen. Holmes finds Irene very interesting. He asks her out on a date.
In the present day, Irene is in the hospital and the doctor tells her that she is unstable. Gregson arrives to meet Holmes. The doctor tells Holmes that Irene is suffering from post traumatic stress. He tells them that Irene was abducted and moved from place to place, and subjected to severe psychological pressure tactics. It seems that someone wanted to destroy her personality. Watson asks the doctor if Irene told him about her abductor. The doctor tells her that Irene mentioned about a man named Mr. Stapleton. He used to play with her mind during the day, and left white flowers by her bedside at night. Holmes tells them that all this has happened to Irene because of him.
He says that Moriarty wanted him to believe that Irene was dead so that he would mourn and get addicted to heroin, and when he recovered, Moriarty sent her back to him. He thinks that Moriarty is way smarter than him. Holmes tells Watson that he wants her to find Irene’s abductors with Bell and Gregson’s help. Holmes decides that he is going to sit this one out. Later, they bring Irene to their house and show her, her room. The next day, Gregson, Bell and Watson go to the house where Irene was found. Bell tells them that the owner of this house stays in Austria and he hasn’t seen this place in a long time. It appears that Stapleton cleaned up the place when he learned that they were coming.
Watson goes through the paints and finds yellow paint pigments. She tells Gregson and Bell that this pigment comes from a particular plant that is grown in Vietnam and it takes a long time to harvest. She says that since this is a rare pigment, they could easily track down the buyer. Cut to flashback, in London, Holmes tells Irene that he wants to spend time with her but she refuses. She tells him that she would like to preserve the integrity of their first encounter. Holmes promises her that he could give her another unique experience. He then takes her to a canal that no one knows of. Irene is thrilled. Later, Holmes notices her birthmark.
He tells her that it is very much like the constellation of auriga. In the present, Irene wakes up from her sleep and she is hysteric. Holmes calms her down. Watson arrives home. Gregson calls her and tells her that the paint pigment was sold to a guy named Duane Proctor. The team goes to interrogate Duane’s brother, Isaac. Isaac tells them that he doesn’t know anything about the abduction. Duane arrives and Gregson and the team go outside to question Duane about the color. Duane tells them that he purchased the color for his brother, Isaac because one of Isaac’s art students wanted it. At that moment, they hear a gunshot. Gregson realizes that Isaac is the culprit.
They rush back inside and find that Isaac has shot an officer and escaped. In the interrogation room, Duane tells Bell that he doesn’t know why his brother did such things. Bell tells him that they found modified weapons in the garage. Duane is shocked. Irene doesn’t remember seeing Duane or Isaac in the house. Elsewhere, Isaac gets a call. Isaac tells the guy that he needs help because his face is all over the news. The guy on the other end of the line tells Isaac that they had to explain his situation to Moriarty. He tells Isaac that they can help him, but before that they want him to run an errand which involves Sherlock Holmes. At home, Holmes tells Irene about his addiction, his stay at the rehab and him being sober with Watson’s help.
Irene tells him that he was broken and he then fixed himself; this gives her hope. Irene goes into her room. Moments later, she screams. Holmes rushes to check on her. He finds a white flower on the bed. Irene tells him that Stapleton was here. Cut to 21 months ago, Irene calls Holmes and tells him that her original piece is ready for him to view. Holmes arrives home but finds a message waiting for him along with a pool of blood. He at once realizes that Sebastian Moran killed Irene. In the present, Holmes takes Irene to a safe place, a garage. He tells Irene that the message was for him. He tells her that he will send her somewhere far from New York, and once he is done with Moriarty, he will come find her.
At the precinct, Gregson, Watson and Bell watch the surveillance footage from Holmes’ house. They see Isaac walk in and out of the house. They figure out that Isaac is still taking orders. Holmes calls Gregson. At the same moment, Watson receives a text from Holmes. He tells her that he is at the precinct and he wants her to come out and meet him. Watson meets Holmes and tells him that Isaac worked for the CIA and his specialty was pressure tactics. She also tells him that she noticed something odd on the surveillance footage. She says that Isaac went straight into Irene’s room when he came with the flower. It looked as if he knew where she was staying.
Watson thinks that Moriarty must have hidden cameras in their house. Holmes says that anything is possible with a guy like Moriarty. He then tells Watson that he is leaving New York with Irene. He tells her that he had told Irene to go some place far so that she can be safe. Irene told him that she would do that only if he agreed to go with her. Watson thinks that this is a bad idea. She feels that this is what Moriarty wants. Holmes tells her that he doesn’t care and that he has made up his mind. Elsewhere, Isaac arrives to meet his employer. He immediately realizes that they are going to kill him. He shoots the man’s bodyguards.
He then shoots the bald guy in his hand and asks him why they wanted him dead. The bald guy tells Isaac that he had become sloppy, and Moriarty could not afford that. Isaac tells him that Moriarty had given standing instructions that Holmes was not supposed to be killed. Isaac wants the bald guy to tell Moriarty that he is going to kill Holmes. At the garage, Holmes notices a change in Irene’s birthmark, the constellation of auriga. He sees that one of the stars is missing. It has been surgically removed. He knows that Moriarty could not have done that. This means that she got it removed. He figures out that Irene has been working for Moriarty. He wants to know since when.
Irene tells him that what he is saying is absurd and that his mind is seeing things that weren’t there. He tells her that Isaac knew which room she was staying in because she told Moriarty. Irene slaps him and tells him that he is inventing reasons because he doesn’t want to go with her. She tells him that she never wants to see him again. She leaves. Later, Holmes arrives home and calls Watson. He tells her that there is a change of plan. He tells her that he isn’t going anywhere. Before he could say anything further, he sees Isaac’s reflection on the lamp. Isaac is pointing a gun at Holmes. Holmes tries to evade the bullet but he ends up getting shot.
He puts up a fight with Isaac and runs upstairs. Isaac catches up with him and tells him that he was planning to kill him earlier, but “she” did not want him killed. Holmes is surprised at the word “she”. Before Isaac could complete his sentence, someone shoots him. It is Irene. Holmes figures out that Irene is Moriarty. The episode ends.