John Tullman: Letective Adventures!

You feel shocked.
"We're taking a case?! WE'RE TAKING A CASE!!!!?"
"Yep!" Mente says excitedly. "A person called us and said that a precious harmonica their great great great grandfather made was stolen. His brother was convicted, but he believes that there is no way his brother could have committed the crime. He wants us to prove him innocent and find the true culprit."
You feel excited, but also a little scared at the same time. What if you fail at your first case? What if Mente thinks that you're not worth mentoring and kicks you out? You're not sure.
What do you say?