The purpose of this study was to examine one mentor as she assisted three beginning teachers to shift their teaching practice to a more robust understanding of a high-leverage practice, discussion-based teaching. The mentor met each beginning teacher where they were in their development, and took on the authority to move each of them forward as they embraced features of a complex practice related to reform-based teaching. Rather than facilitating learning ordinary practices, this mentor provided an image of an exemplar. She provided an image of the possible as she helped beginning teachers learn the power of local knowledge from teachers who took on teacher educator roles, who pushed back against institutionalized norms of learning to teach alone or learning to teach the scripted curriculum.