Co-designing with mission-driven stakeholders means a need to adhere to their societal value pursuit, especially when engaging with social innovation projects. Values in relation to design has been a focus within HCI, for instance in the form of Value Sensitive Design, Design for Values and Reflective Design. This article focuses on the specific cases where the non-designer partners in the projects are mission-driven, with a high level of value competence. The article follows a design process in a social innovation project aimed at designing for meaningful meetings in public environments. The study adopts a Research though Design methodology, with the design process informed by Value Sensitive Design. The study focuses on how the mission-driven stakeholders are engaged in value conversations in the different stages of the design process. It was found that also already explicated values needed elicitation and conversations, and that values were re-interpreted throughout the whole design process. Mission-driven stakeholders were found to have high value competence, but needed scaffolding to bridge between abstract values and concrete design choices. The study shows that value conversations remained important throughout the project, that they permeated all project activities, and constantly resurfaced and were re-negotiated. There was a constant interplay between value conversations and manifesting values in sketches, probes and prototypes. This interrelated with increasingly granular value discussions, and more advanced design proposals opened for new types of value conversations. Value conversations were found to be aided by activities that were playful, tangible, theory informed and recurring. Normal design activities, such as prototyping, could cater for value conversations, but this required an adaptation to how such sessions were carried out, by adding layers of value reflection.