Last year, a group of American, Russian, and Kazakh scientists gathered at a mountainside in Kazakhstan to announce that they had finally secured vast stores of plutonium that the Soviet Union buried there years earlier, at the height of the Cold War. The ceremony marked the end of a 17-year, $150 million project to secure the abandoned nuclear testing site, but received relatively scant media attention until last week, when the Washington Post published a thorough account of how the mission came to be. Piecing together interviews from various scientists who worked on the project, the Post details how Russian and American authorities overcame lingering diplomatic tensions and serious risks to keep the plutonium out of the hands of terrorists or rogue states — but will it stay that way?