The episode begins with an incident that took place six months ago. A girl arrives on the subway platform, and she spontaneously receives some roses from a guy. The girl tells her friend over the phone that a guy was on his way to meet his girlfriend, and his date got cancelled, and he did not want the roses to go to waste. That is why he gave them to her. The train arrives, and we see that the same guy push this girl in front of the train. Watson is having drinks with her friends and she tells them that she is enjoying her new job. She receives a call from Dr. Caruso about her new client. She wonders what kind of a name is Sherlock.
Cut to present, Watson breaks into a car and tries to cut off the alarm, but she is unable to do it. Sherlock’s new sponsor, a former car thief turned security man, is in the car and he turns off the alarm. He is teaching Watson some tricks, so that she could help Holmes with his job. Holmes messages Watson, asking her to reach home immediately. Watson arrives home and Sherlock tells her that, in return for the loan he gave him recently, his father wants him to do some investigative work for him. Watson and Sherlock arrive at their new client’s office. Philip Armistead and his assistant, Rebecca, arrive. Philip tells him that it is Rebecca who needs help. Rebecca tells Holmes that her sister, Callie, has been missing for the last six months. She fears that her husband might have done something to her.
Rebecca shows them a video that Callie had recorded. The video was for Callie’s husband. She tells her husband that she does not love him anymore, and that she is going away for a while. She says that she was inspired by the woman who was killed in the subway, and thinks that life is too short to spend with someone she didn’t love. We see that Holmes is more intrigued by the subway pusher’s case. Rebecca tells Holmes that when Drew, the husband, showed her the video, she initially thought it was normal. She says that Callie used to disappear for a while, because she was very fragile. She says that her suspicions started when days grew into weeks, and Callie did not return. She filed a complaint, and the cops told her that Callie hadn’t used her credit cards since the time she disappeared.
Rebecca thinks that this video is a fake. She believes that Drew forced Callie to record this video so that, after he killed her, he could convince the cops that she ran away. Rebecca also tells Holmes about a trunk that is missing. The trunk is her grandmother’s, and big enough to hold a body. Callie kept the trunk with her, but the deal was that she would return it to Rebecca when she moved. She says that she found the trunk missing, after Callie disappeared, the first time when she went to meet Drew. Sherlock takes Watson aside, and tells her that he inferred from the video that Callie meant every word that she said. He tells Watson that this is going to be her first independent case, because he is planning to take up the subway pusher’s case.
At home, Holmes watches the video footage of the subway murder. He tells Watson that the pusher made sure his face was turned away from the camera and this murder seems premeditated, but he doesn’t have anything more on the killer. Watson doesn’t have much on Callie’s disappearance.
Watson forgot to meet her friend, Emily, who is waiting for her at the bar. They decide to meet the next day. The next day, Watson arrives to meet Drew, and Drew tells her that Callie was a complicated person. He tells her that Callie left him once before but, when he convinced her, she came back. He doesn’t know what happened the first time. Drew tells Watson that, the second time, Callie seemed distant and depressed, especially after the woman’s death in the subway. He tells Watson that Callie took the trunk. He wants to find Callie, only to make sure that she is alright.
Watson leaves the office and calls Sherlock, to tell him that she feels that Drew killed Callie. She plays the tape of the statement that Drew gave the police, and she tells Holmes that he said those exact words he told her. She feels that this statement is rehearsed, and she feels that something is not right. Holmes takes out a burner phone, from a box, and sends Drew a message saying that he knows that he killed her and he knows what he did with the body. Holmes is sure that this message will throw Drew off guard, and he might reveal something. Homes then heads to the police station, to interrogate a suspect on the subway pusher case.
Holmes interrogates his suspect, and we learn that the man worked in the same office with the woman, Vivian, who was killed six months ago. The man was following her, and shooting her video. Holmes had noticed this man in the security footage. Gregson and Holmes pressure this guy, and he admits that he was stalking the woman and shooting her video. He was in the subway on the day of the murder, but he swears that he did not kill the woman. He says that he was wearing a hat and a scarf, not a hoodie. There is proof that he was shooting a video that night, as well, so he couldn’t have pushed the woman. Gregson and Holmes check the footage the man recorded. Holmes is upset to see that this video doesn’t reveal the face of the pusher. It doesn’t even show the patch on the pusher’s jacket, which he had noticed in the surveillance footage from the subway. Watson calls Holmes, from her stakeout, and tells Holmes that Drew hasn’t done anything out of the ordinary. Holmes reminds her of her date with Emily, and tells her that Alfredo, the sponsor, will keep an eye on Drew. Holmes goes back in and watches the video again. He notices that a busker stops, mid-song, and leaves the platform when he sees Drew. This means that the busker knew Drew and what Drew was about to do. He tells Gregson that they need to find the busker.
Watson meets up with her friends. They are surprised to learn that she has quit her job, and moved in with a recovering drug addict. Watson doesn’t like it, and is about to leave. They tell her that they are concerned about her. Alfredo texts Watson, saying that Drew is on the move. Watson joins Alfredo, and they see Drew moving a trunk out of the storage. Watson recognizes the trunk. When Drew goes back inside, Watson decides to break open the trunk, but she gets busted by the security guard. Drew arrives as well. Watson tells the guard that she believes that Drew killed his wife, and put her in the trunk. The guard asks Drew to open the trunk. It is empty.
Watson is in jail, and Holmes bails her out. He tells her that Drew told the cops that he sold the trunk, partly out of spite. He also knew its worth, and his gallery was facing some financial difficulties. He did not tell Rebecca, because the trunk was not his to sell. The storage space belonged to the guy who he sold the trunk to. Drew was taking the trunk back, so that he could return it to Rebecca. Holmes tells her that there is a paper trail that confirms all this. Holmes then tells her that they will solve both cases together. Holmes and Bell go to meet the busker, and Holmes knows that the busker is also a pickpocket. The busker tells Holmes that he tried to pick the pusher’s pocket, but he got caught. He left because, when he saw the pusher on the platform, he feared that he will alert the cops. Holmes knows that every pickpocket studies the coat of the guy they are going to pick, so he asks the busker to describe the patch on the pusher’s jacket. The busker describes it, and Holmes wants to show it to the public.
Watson decides to apologize to Drew, and have the charges dropped. She then goes to meet Rebecca, and apologizes for her mistake. Watson then looks at a photo frame, which displays Callie wearing a jacket with the patch that the busker described, and Rebecca tells Watson that it was Drew’s jacket. Watson asks her if Drew had a beard and Rebecca tells her that he did, but he shaved it off after Callie disappeared. Holmes and Watson then go through all the links, and infer that Drew was the subway pusher. They wonder why. Holmes also wonders what compelled Callie to leave Drew for the second time, after the subway murder, when she didn’t know that he was the pusher.
They bring in Drew for interrogation. Drew denies the accusations. We learn that, 18 months ago, a woman holding flowers was pushed in front of the train. This was the same time when Callie left him the first time. Watson and Holmes then describe what could have happened. They think that Callie recorded this video 18 months ago, and was talking about that murder. They feel that Drew came up with a plan to murder his wife and get away with it. Drew pushed Vivian in front of the train, six months ago, and then killed Callie and used the video to explain her disappearance. All he needed was a subway pushing in the present, involving a woman holding flowers, and so he killed Vivian.
They tell Drew that he deleted the original email, from Callie’s account, that was sent 18 months ago. Then, 6 months ago, he resent it to his email. They found the original video, archived on the server, and it was sent 18 months ago. At home, Watson changes the job on her dating profile from “sobriety counselor” to consulting detective. The episode ends.