The heterogeneous backgrounds, languages and proficiencies students bring to the classroom have always been a key challenge facing schools that wish to implement heritage language programmes. In this article I describe the evolution of one high school's approach to heritage language education and some of the roadblocks they encountered in attempting to boost student participation in heritage language classes during the senior-secondary years. Drawing on ethnographic observation of over two years as well as interviews with staff and students, I explore the complex ways in which top-down language-in-education policies work to favour some languages and types of speakers over others, and how course content and scheduling affect students' decisions to (not) study their heritage languages in the senior years. In doing so, my aim is not to argue the superiority of any one approach to programme design but, following Jaffe [2011. "Critical perspectives on language-in-education policy: The Corsican example." In T. L. McCarty (Ed.), "Ethnography and language policy" (pp. 205-229). New York, NY: Routledge], to expose the implications of various choices and thereby help schools and policy-makers to better achieve their goals in running heritage language programmes.