General Percy Hobart's answer to Rommel's Atlantic Wall was a fleet of tanks built to do things tanks were never meant to do: swim, flail, flame, and bridge. The film tracks the design and deployment of Hobart's Funnies, from amphibious Sherman DD tanks fitted with canvas screens and propellers to Crab tanks whipping chains ahead of them to detonate mines, to Churchill Crocodiles spraying fire from converted turrets. Archival footage and reenactments follow the machines onto the D-Day beaches, contrasting their success on the British and Canadian sectors with the American refusal to adopt most of them, a decision the film ties directly to the heavy losses at Omaha Beach. The prefabricated Mulberry Harbors get their own section, showing how the Allies solved the problem of supplying an invasion without a port. Interviews and period footage explain Churchill's personal backing of Hobart's unorthodox engineering, and the film makes a clear case for how much these strange machines mattered to breaking through the German defenses.