Story mapping is used in schools to promote children's understanding of stories and narrative structure. As a collaborative activity, it can support creativity and facilitate group interaction. However, most techniques used in primary schools rely on visual materials, which creates a barrier to learning for children with visual impairments (VI). To address this, we set out to design a collaborative story mapping tool with a group of children with mixed visual abilities and their teaching assistants. Using co-design approaches over ten workshops, we designed and prototyped different ideas for engaging children in storytelling and design.We present our co-design process and findings, and the resulting story mapping system. We outline how using multisensory elements can facilitate creativity and collaboration to help children with mixed visual abilities create and share stories together, and support learning and social inclusion of VI children in mainstream classrooms.