This case study analyzed the ways a native Spanish speaker of high-beginning English proficiency and his teacher negotiated an extended writing task in a tenth-grade mainstream humanities course. An "interactional histories" analysis demonstrated the teacher's pedagogical and conversational moves to adapt the academic task and the moves of teacher and student to co-construct this assistance. The study revealed how opportunities for language minority students' literacy development are locally created through teacher-student interaction but reflect linguistic, cultural, and institutional concerns related to academic performance and achievement.