Intrigued by the overwhelmingly positive response to the needle and syringe exchange program (NSP) by people who inject drugs in Stockholm, this article sought to untangle harm reduction in a prohibitionist drug policy context. The article drew on assemblage thinking and used semistructured individual interviews with 32 people who inject drugs, and three focus groups with staff at the Stockholm NSP. The aim was to dissect harm reduction in the form of NSP and how it worked to move people who inject drugs towards or away from drug-related harm. The analysis identified how bodies such as the NSP regulations, the setting, and stigma gathered in ways that reduced the capacity to move forward and enroll, as the inclusion of the NSP in the assemblage would decrease the capacity to uphold other connections considered to be more important. Regular NSP visitors however described how free injecting equipment, staff care, continuity, and trust were important objects that gathered in ways opening up for movement towards less harm. Fiercely, these profoundly caring experiences at the NSP could also block new becomings and moves forward as people who inject drugs, discouraged from previous negative experiences of other service providers and structural stigma, refrained from other connections that could improve their wellbeing. They risked becoming locked in at the NSP and similar services. A significant consequence of the agential cuts of us researchers, the staff, and policymakers alike, targeting primarily those that do access and benefit from harm-reducing interventions, is that alternative solutions embracing also those locked out and locked in become unimaginable. [Author's abstract]