who wrote the storyline of this episode?
Jennifer Celotta
The Duel (The Office)
The episode was written by Jennifer Celotta and directed by Dean Holland, the show's long-time editor making his directorial debut. 
when does andy find out angela is cheating In the episode "The Duel". which major series is this episode part of? "The Office" name the main characters (not the guest characters) appearing in that episode. Andy Bernard, Angela Martin, Dwight Schrute to name some. which actor plays the first character? Andy Bernard which actor plays the first character? Ed Helms which actor plays the second character? Angela Kinsey and who plays the third character? Rainn Wilson are there any guest characters appearing in this episode? UNANSWERABLE can you summarize what is the storyline of this episode? Andy learns his fiancee Angela is having an affair with Dwight, and the two challenge each other to a physical fight to win her affections. Meanwhile, Michael travels to New York City for a meeting with David Wallace, where Wallace seeks managerial advice from Michael due to the poor financial condition of the fictional company, Dunder Mifflin.
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The Duel (The Office) [SEP] Introduction
That scene was shot over the course of six hours in an exterior parking lot set, with Helms and Wilson providing their own stunts.