Secret Service agent Brass Bancroft (Ronald Reagan) goes undercover to infiltrate a saboteur ring that is after an experimental energy weapon (the "inertia projector") that is about to be tested onboard a giant Navy dirigible. The slim story resembles a forties serial without the numerous cliff-hangers as the Bancroft almost single-handedly defeats nefarious spies led by Garvey (James Stephenson) and Rumford (Victor Zimmerman) through a series of fights, chases and daring-do. Reagan is pretty good as the incredibly lanky Bancroft but his sidekick 'Gabby' (Eddie Foy) who, with his put-upon fiancée Dolly (Helen Lynd), provides some dated comic-relief, get tiresome quickly. The pre-war film is a bit jingoistic but seems more concerned with socialists than with Nazis or the Japanese - at one point Bancroft is roughed-up and 'arrested' after being accused of being a 'wobbly' (a member of 'The Industrial Workers of the World'). The film moves through its brief running time briskly and despite some ludicrous touches (the clandestine saboteurs sport very obvious tattoos that everyone seems to recognise), the story is entertaining and the special effects, such as the downing of the huge dirigible quite well done (for budget and genre). The low-budget, somewhat misleadingly titled thriller may be best known for a plot involving a theoretical energy weapon that (in the hands of the USA) would bring about world peace and starring future President Reagan, who (four decades later) would endorse SDI 'Star Wars', an initiative involving theoretical energy weapons that (in the hands of the USA) would bring about world peace.