In 2008, five ‘serious untoward incidents’ occurred on a small maternity unit in a hospital in the UK. The prevailing view, held by clinical staff, hospital managers and executives, was that these events were unconnected and did not signal systemic failures in care. This view was maintained by the testimony of staff and governance procedures which prevented the incidents from being considered together. Drawing on the inquiry report of the Morecambe Bay Investigation (2015), I examine how the prevailing view was built and dismantled, eventually being replaced with a very different description of events. Overturning this view required affected parents to engage with governing bodies and legal processes, challenge clinical staff, lobby for inquests, mobilise social media and the national press. Tracing how different descriptions of events weaken or gather force as they travel through different forums, processes, and are presented to different audiences, I explore the sociology of knowledge around establishing failures of care.