To complete one of Sadie Adler’s Errands in Red Dead Redemption 2 you must find the Harmonica Location. The guide below shows where to find the Harmonica in RDR2:
The Harmonica is located in the hut east of Flatneck Station. It’s inside the hut on a cupboard. There is one rancher in the area and he will attack on sight.
In order to deliver it you must get Sadie Adler’s errand request first. She gives it to you automatically after main mission “Further Questions of Female Suffrage” in Chapter 3. Fulfilling 5 errands is a requirement for the Errand Boy trophy and achievement. This errand is missable, you must complete it before the end of Chapter 4! Bring back the Harmonica to Sadie at your camp to complete this Companion Request.
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