In 2015 the United Kingdom closed out a debt that partly originated in the Napoleonic Wars, rolled over for two centuries through perpetual bonds. That fact opens a deep dive into the war bond: a debt security that gives the military immediate cash while soaking up civilian money to prevent inflation. We trace how war finance shifted from elite banking families like the Fuggers and Rothschilds to the collective savings of millions once World War I broke every traditional model, and how governments had to teach ordinary people what a bond even was.

Because retail war bonds usually paid below-market interest, states built an emotional architecture to override rational finance. The episode covers Austria-Hungary's leveraged bond loans to schoolchildren, Charlie Chaplin's film The Bond, Canada's staged Nazi invasion of Winnipeg on If Day in 194 ...