Early reactions suggest that secondary teachers need support implementing the Common Core State Standards, specifically when teaching close reading strategies with complex disciplinary texts to vulnerable readers. This mixed-methods study conducted in a formative experiment paradigm (Reinking & Bradley, 2008) aimed to provide explanatory theories generated by applying a grounded theory approach to data analysis. An ethnographic case study design framed the grounded theory (Glaser & Strauss, 1967) and the formative experiment. I wanted to understand how two teachers adjusted their curriculum and instruction to create a more rigorous experience for vulnerable readers. I also sought to explore how such an approach affected the academic identities of these students. Teacher surveys, teacher interviews, student interviews, student surveys, student work, reading assessments, classroom observations, and teacher planning sessions provided evidence about how readers in two classrooms make sense of text and the strategies that support their comprehension and engagement during two curricular units that involve close reading of disciplinary texts. The units were used by students in two Special Day English classrooms at two different school sites and were co-designed by each high school teacher and myself. Reflections upon the first curricular unit informed the planning for the second curricular unit in each class. Also, I followed three students into at least one of their other disciplinary classes to understand their experiences with discipline-specific literacy instruction, both in the language arts and their disciplinary classes. Finally, I interviewed students about their in-school and out-of-school literacy practices, again to look for evidence of transfer from the units to their everyday repertoire of practices. Results indicate that both teachers, as they implemented the collaboratively planned lessons, asked predominantly open-ended questions that expected students to include textual evidence in their responses and did not have predetermined answers. This behavior was contrary to what I expected at the beginning of my study because I expected teachers might have predetermined answers. When responding to each teacher's instruction, students referenced the text in supporting the claims they developed on their own. In both classrooms, some of the students' academic identities improved during the study. All students reported rich relationships with text outside of school; however, only some students experienced success with reading complex disciplinary text in their English class. Overall findings suggest a positive effect of open-ended tasks that require students reference both the text and the knowledge that they bring to the task in forming arguments and applying understandings gained while reading. Future studies including a greater number of teachers from a range of disciplines who implement instruction with more students over a longer period of time would be beneficial in developing a more robust database about the power and influence of close reading practices.