This chapter describes the encounter between an antiretroviral therapy (art) research project and an extended family in rural East Africa. The meeting of research and lived realities involves multiple relations between the HIV virus, involving international science, the state, individuals, kinship networks, and medicine. The analytical focus explores the effects of the cutting and creation of these relations and networks in practice. The networks are founded, held together, and also cut by associated values and ethics of larger wholes, in this case of kinship, bioscience, and modernity. The chapter provides an insight into what happens “when the virus works,” not primarily at a biological level but more so at a social level: When family members in existing rural networks are propelled into, and chose to do, HIV work and to be gatekeepers and brokers of access to art made available by medical science projects and other family members are clients and objects of study in the projects.