The Cassini-Huygens mission has revolutionized our understanding of the Saturn system. In particular, it has shown that the diminutive moon Enceladus is one of the most geologically active and exciting bodies in the solar system. This activity is tied to the existence of a subsurface ocean of liquid water that may be habitable or even inhabited. However, to make progress on the question of life, we need to understand the geochemical context. In this talk, I will show how Cassini INMS and CDA data of Enceladus’ plume can be coupled to constrain the geochemical conditions of its ocean, with a focus on the fundamental parameters pH and oxidation state. I will then discuss how the process of serpentinization provides a framework for understanding possible prebiotic and biological processes on Enceladus. This sets the stage for future missions to Enceladus to test for a serpentinization-life linkage.