A myriad of personal and contextual factors are important in understanding how preservice teachers learn to teach and why they adopt or reject certain teaching practices. Activity theory was used a framework in understand preservice teachers' experiences teaching writing during a field experience at a juvenile detention facility. The purposes of this study were to (a) to examine the pedagogical tools and practices that preservice teachers implemented during a field experience at a juvenile detention facility (b) to understand why they implemented these pedagogical tools and practices, and (c) to explore preservice teachers' perceptions of how they were shaped by the activity setting, the detention center. Results found preservice teachers entered the setting with very specific expectations about the arena, and these perceptions shaped their pedagogical choices.