School-university partnerships can be fertile environments for collaboration by educators and researchers. So far, studies of these partnerships have mostly focused on identifying partnership challenges and presenting them as difficulties to be prevented or solved. In this case study, we examine challenges in relation to the partnership's future directions, using a boundary-crossing perspective. We pose that some challenges, experienced by partners as discontinuities in perspectives and/or practices, are connected to envisioned opportunities for boundary crossing, and thus hold potential for partnership advancement. We provide proof of concept by analysing the challenges and opportunities of a STEM school-university partnership between 48 high schools and two universities (one research university and one applied sciences university) that offers an enrichment program for secondary school students and teachers. Data involved partnership documents, 12 semi-structured interviews, and 42 survey responses from partners of schools and universities. By presenting this case study, we show that partnership challenges are connected to expansive opportunities posed by partners, and this connection is relevant to the advancement of the program and the collaboration between partners, as well as the emergence of new purposes.