October 6, 2012: 109 adults simultaneously threw their heads back and shouted "I discovered!" at the top of their lungs. Slightly mangled bright-green paper helicopters littered the floor. The class was six minutes into a daylong journey of discovery, during which this group of volunteer trainers would learn to facilitate a curriculum that uses inquiry-based science to teach youth development concepts. What would it take to increase the number of youth-serving volunteers who can competently lead science, technology, engineering, and math (STEM) activities? This question has guided the authors work in the Inquiry in the Community project, launched in 2008. Along with Girl Scout staff colleagues and many dedicated volunteers, the authors have created a system for embedding inquiry-based science into a youth development organization. They achieved this goal by training staff and volunteers on inquiry facilitation techniques and then building support networks to reinforce these new skills. When co-author Stephanie was accepted into the National Afterschool Matters STEM Practitioner Fellowship, the authors decided to use the action research component of the fellowship to dive deeper into a facet of Inquiry of the Community they hadn't yet been able to investigate: the experience of volunteers participating in the project's train-the-trainer program. The lessons learned in the resulting action-research project can apply to other train-the-trainer efforts in afterschool and youth development. Stephanie takes over the story in this article to describe how she and co-author Jen Sorensen implemented the program and how Stephanie's action research examined the volunteers' experience.