This article explores the worship of La Santa Muerte through a geo-mapping of street altars in Mexico City followed by an ethnographic analysis of the devotees' relationships with the saint. I find that this saint has gained momentum among the fast-growing prison population over the last two decades. In contrast to studies that emphasise the desertification of mass incarceration elsewhere, this study finds that La Santa Muerte connects families across the social abyss of imprisonment. I suggest that the family-like relationships that devotees maintain with this saint are crucial to understanding her success. Rather than a one-dimensional sacred defender of criminals and police she is adopted by prisoners, prison officers, police and their families as a capricious ‘family member’, embracing the same ambivalence as the forces she helps to navigate.