This talk describes the disinformation campaign targeting the Syria Civil Defense (or “White Helmets”), a humanitarian response group that works in rebel held areas of Syria. The White Helmets provide medical aid, search, and rescue to people affected by the civil war in Syria. They also document the impacts of atrocities — including airstrikes and chemical weapons attacks — perpetrated by the Syrian regime and their Russian allies. For several years, the White Helmets have been the target of a campaign to undermine and delegitimize their work. In this talk, I describe a multi-study research effort that reveals how this multi-dimensional, cross-platform campaign “works” — including a look at the media ecosystems that support the campaign, the networks of actors who collaborate to produce and spread its narratives (including government agents and “unwitting crowds” of online activists), and the “work” that these actors participate in, using the affordances of social media platforms to connect, recruit, organize, promote their messages, attack opposing messages, and otherwise advance the goals of their campaign.