Henry Morgenthau, the U.S. Secretary of the Treasury during World War II, opens an investigation into Swiss banks doing business with Nazi Germany and finds the trail runs straight through London and New York. The film follows his team's archives into the Bank for International Settlements, founded by Bank of England and German financiers as a supposedly neutral clearinghouse that in practice laundered plundered European gold. Its board includes Nazi officials Walther Funk and Hjalmar Schacht, and its president, the American banker Thomas McKittrick, is shown socializing with them throughout the war. An American bank keeps a Paris branch open under occupation and, with its head office informed, freezes the accounts of French Jews, cutting off the money that might have bought their escape before deportation. Interviews with surviving members of banking families and Morgenthau's own investigators, paired with archival documents, trace how the inquiry loses momentum after Roosevelt's death in 1945 and stalls further when Morgenthau's staff face Communist accusations during the McCarthy era.