Captain Stottlemeyer: Don't do it.
Adrian Monk: Don't do what?
Captain Stottlemeyer: Break my heart. You're thinking about planting evidence in Kloster's house. Monk, I've been a cop for 30 years. I've had this conversation nine times. I never thought that I'd be having it with you. There's a line. You step across it, and you're gone for good. There's no going back.
Adrian Monk: You don't understand.
Captain Stottlemeyer: I do understand. I've been there. I've had cases like this, cases you couldn't shake. Sometimes you have to let it go.
Adrian Monk: Let it go?
Captain Stottlemeyer: We have to move on. There's a city- A city full of people. Other people that need our help right now.