There is increasing recognition of the need for innovative, integrated, and multidisciplinary strategies to improve neurological health. The incorporation of serious games and virtual reality (VR) into personalized neurorehabilitation programs offers promising avenues for future applications. In this context, functional magnetic resonance imaging (fMRI) provides a powerful tool to assess the effects of these therapies on brain activity. This study investigates neuroplasticity in a 42-year-old post-stroke patient using fMRI and a motor imagery protocol embedded within a VR-based serious game. The intervention consisted of 18 personalized sessions targeting upper limb motor function. fMRI scans were acquired before and after the intervention, alongside clinical assessments using the Fugl-Meyer scale. Image processing was carried out using FSL, FreeSurfer, and 3D Slicer, enabling voxel-based quantification across functionally relevant brain regions. Statistical analysis revealed a significant increase in activation associated with bilateral upper limb movement, indicating enhanced brain reorganization following the intervention. These results demonstrate the potential of immersive serious games combined with fMRI as an effective approach for monitoring neuroplasticity in rehabilitation settings.