<p>In response to the growing emphasis on addressing global socio-scientific issues like climate change and viral pandemics in K-12 education, we designed three socio-scientific units for middle school science. We call this curriculum Grand Challenges (GC). The GC curriculum shifts from traditional methods to a focus on socio-scientific issues that resonate locally and globally and prepare students for future complexities. GC is a response to the evolving landscape of science education which emphasizes transformative, future-focused approaches that engage students with science content through contextualized, disciplinary practices. This study explores the implementation of the GC curriculum by two teachers, highlighting their choices and the impact on instruction. The findings reveal the crucial role of teachers in actualizing innovative curricula, the challenges of adopting new practices, and the need for robust support systems. This work contributes to understanding how to effectively integrate socio-scientific issues into science education, fostering critical thinking and global citizenship among students.</p>