Integrating computer science (CS) content into existing STEM curricula emerges as a viable solution to broadening rural students' participation in CS, but rural students have a significant proficiency gap in science and mathematics. By focusing on an English language arts course as the context for CS integration, this exploratory study examined the impact of a robotics-based intervention integrated into a high school language arts class on rural students' CS self-efficacy. A convergent mixed methods design was applied to collect and analyze qualitative and qualitative data separately. Quantitative results confirmed that the integrated robotics-based intervention significantly improved rural students' CS self-efficacy. Qualitative findings provided insights on how embodied learning and mastery experience facilitated by the robotics-based intervention fostered rural students' CS self-efficacy. The findings from the two sources of data were integrated, shedding light on the potential of curricular integration in language arts classes for broadening rural student participation in CS education.