(Joan tries to connect with Sherlock, who keeps pacing)
Joan: My name is Joan Watson. I've been hired by your father to be you sober companion. He told me he was going to email you about me. I'm here to make your transition from your rehab experience to the routine of your everyday life as smooth as possible, I will be living with you for the next six weeks. Which means that I will be available to you twenty four seven.
Sherlock: (Stops pacing and looks Joan in the eyes) Do you believe in love at first sight? I know what you're thinking. Love is a cynical place and I must be a cynical man, thinking a woman like you would fall for a line like that. The thing is, it isn't a line. Please hear me when I say this. I have never loved anyone as I do you right now, in this moment. (Without losing eye contact with Joan, he turns on the TV and an actor repeats the line.)
(Joan follows him from room to room while he moves like she's not there)
Joan: Care to explain why you broke out of your rehab facility the same day you were being released?
Joan: You were bored?
Sherlock: I am bored, right now. It happens often. You'll get used to it. Regarding our mutual friends at Hemdale, I'd say they should be thanking me for exposing flaws in their rubbish security system.
(Sherlock explains that the woman who left did not use chemicals to get Sherlock high.)
Sherlock: I actually find sex repellent. All those fluids and all the sounds. My brain and my body require it to function at optimum levels, so I feed them as needed. You're a doctor. You understand.
(Sherlock brings Watson to the crime scene)
Sherlock: Tell me, how do clients typically introduce you.
Watson: What do you mean?
Sherlock: I mean, I find it hard believe they'd actually tell someone that they've been assigned a glorified helper monkey.
Watson: Helper monkey?
(Sherlock corrects Watson for allowing Detective Gregson to bar her from the crime scene.)
Sherlock: Consider this my place of business. Consider every wretched hive of depravity and murder in this city, my place of business. Unless of course, you don't believe you have the stomach for the work I do.
(Watson asks Sherlock how he guesses)
Sherlock: I don't guess I observe. And Once I've observed I deduce.
(Sherlock and Watson speak on the roof of the brownstone)
Sherlock: The simple truth is, I don't need you. I'm finished with drugs. I won't be using them again. My advice, take a six week holiday. I promise I won't tell the Pa.
(Things come to a head when Watson calls Sherlock on being wrong, just to be corrected.)
Watson: It's incredible, the way that you can solve people just by looking at them. I noticed you don't have any mirrors around here.
Sherlock: What is that supposed to mean?
Watson: I think you know a lost cause when you see one. (Joan takes her laptop and starts to walk away) Tomorrow I'll arrange for a new companion. Tonight I've got plans.