S4, E6: Natalie is out running errands for Monk when she can't believe her eyes: crossing right in front of her in a restaurant is a woman who appears to be Trudy Monk! Trudy is meeting with an older man named Zach Ellinghouse, and Natalie overhears her telling Zach that she faked her own death to protect her family from a dangerous extremist group that was the subject of a newspaper story she was writing. Natalie tries to warn Monk about Trudy, but he's in such a good mood, she doesn't have the heart to tell him the disturbing news.