Michael Rowan is an addict and a serial killer who befriends Sherlock Holmes. He works at an architecture firm.
|Michael is first seen outside a support group meeting where he introduces himself to Sherlock and credits him for helping him stay sober. Michael indicates that in a past meeting, Sherlock said that committing himself to his work helped with his sobriety so Michael did the same. Sherlock doesn't know this commitment is to Michael's serial killing. He gives Sherlock his business card and offers to meet. Sherlock calls Michael to go to a meeting while Michael is burying a woman he killed, Polly Kenner, in the woods. ("An Infinite Capacity for Taking Pains")
|In his office, Michael is looking at the social media of Polly Kenner as Holmes meets him for coffee. They discuss Holmes' medication and his fear of relapse. Michael calmly advises Holmes to trust his support system. Days later they meet for coffee again and Michael says he's been thinking about Holmes' struggles and a way to help. He tells Holmes about Polly Kenner, that she is a heroin addict and hasn't attended support group nor shown up for work. Michael asks Holmes to see if he can find her. ("Pushing Buttons")
|Michael is able to deduce where The Brownstone is and unexpectedly visits Holmes. He asks how Sherlock is doing and finds he's flustered. Michael compliments Sherlock's commitment to his work and its contribution to his sobriety but Sherlock says following the program is what keeps him sober. Michael asks if Sherlock has any leads in Polly Kenner's disappearance but Holmes has left it to the police as she frequently drops off the map after relapsing so, Michael leaves. Later, at a support group meeting that Sherlock doesn't attend, Michael tells those there about his attempts to "help" Sherlock with a "project" but it hasn't worked. He vows to get louder in order that Sherlock hears him. ("Bits and Pieces")
|Captain Gregson's daughter, police sergeant Hannah Gregson is at home, when her roommate Maddie tells her that a man just hit her car and wants to see her outside. The man is Michael who exchanges information with Hannah seemingly in order to pay for the damage he's caused. Later that evening, Michael is seen sitting in his car as Hannah comes home and finds Maddie murdered. ("Give Me the Finger") Maddie has been staged with clothing from past murder victims. Watson discovers that the earrings on Maddie were Polly Kenner's. Sherlock tells Michael that Polly might be dead and describes what happened to Maddie.
|After leaving Michael's, Sherlock is convinced he is the killer. Holmes and Watson stake out Michael's house but Watson leaves him alone to get medication for his PCS. Sherlock wakes in a hospital, having been taken there by Michael after passing out in the car. Michael explains that he used heroin to dull the hurt of the urges he has to kill. Once he stopped using, he needed to kill. He believes he and Sherlock can help each other. Michael is one step ahead of everyone's investigations, pushing Holmes into buying heroin to dose Michael into a confession. He and Watson wait outside Michael's home but when he doesn't show, Watson breaks in. Michael calls Sherlock to tell him that he's left NYC but will be back when Sherlock has recovered from his PCS. ("Sober Companions") Holmes discovers that Michael arranged the theft of his medical records and expects that he will return. ("The Worms Crawl in, the Worms Crawl Out")
|In the wake of a strangling death of Rachel Garner that fits Michael's M.O., he appears at the 11th Precinct but will only speak to Holmes. Holmes tries unsuccessfully to get Michael to confess to past murders but Michael acts hurt and leaves. Holmes ambushes Michael in the parking garage at his work intent on intimidating him. Michael tells Holmes he should be thankful he gave him time to get better and also indicates that Garner's killer hated her. Holmes sees Michael's key chain and with Everyone's help, is able to find that Michael was living in Albany. A search of his Albany house reveals many photos of women he was stalking and one that proves he wan't in NYC when Garner was killed.|
|One of the leads Watson was pursuing, William Bazemore, an addict who Michael knew and helped, commits suicide after Watson shows Bazemore strong evidence that Bazemore's husband was killed by Michael. Enraged, Michael surprises Watson in the basement of the Brownstone and beats Watson, concussing her and breaking two ribs. He admits to killing Bazemore's husband but while looking at an evidence board of himself, Watson escapes and locks herself in a second floor room containing the wreckage of a helicopter from a previous case. When Michael breaks in, Watson stabs him in the shoulder with a tail rotor blade. Michael flees, bleeding heavily. A day later, Michael is found dead in a garbage dump. The FBI demands Watson's surrender as the prime suspect. ("Fit to be Tied")|
|FBI Agent Mallick reveals to Watson that when Michael was murdered, he was leaving a voicemail for Bazemore and he cried out "Joan" while being killed. Holmes breaks into the Morgue and steals the autopsy report on Michael. He enlarges photos of Michael's corpse and examines them with Watson and observes Michael had a small penis. Watson deduces that a former Vietnam War field medic stitched up the stab wound she gave Michael. Holmes is able to find the medic, an addict named Denny Mulgrew that Michael knew from support meetings. They then discover that Michael was killed at Mulgrew's house. With evidence provided by Detective Bell, Holmes finds that Captain Gregson erased video evidence at a garbage depot to cover up that Michael's killer was his daughter Hannah who beat Michael to death. ("Whatever Remains, However Improbable")|