S4, E11: It’s late, and Monk and Natalie are at a deserted highway rest area. They’re there to meet a man who claims to have information about Trudy’s murder. Monk has brought an envelope of reward money, and he makes Natalie hide so he can meet the man alone. When the man turns out to be a phony, Monk refuses to give him the cash. A struggle ensues. The man clunks Monk over the head, steals the reward money and Monk’s wallet, and dumps Monk’s unconscious body on a flatbed truck. When Natalie reappears, Monk and the man are both gone.