British preparations for a German bombing raid are examined, as well as the resultant destruction caused by the raid and the defences mounted by Britain's Royal Air Force. Canadian preparations for air defence, should the country be attacked during the then-current Second World War is also highlighted.
The narrator describes the fall of France, leaving Britain almost defenceless. British forces are vastly outnumbered, but the British people are calm. The narrator explains that this is because in a democracy the people as a whole are involved in the decision to fight. Hitler's masterplan to subjugate Britain is described. Hitler begins by attacking convoys and ports, but fails to destroy them. The RAF are outnumbered "6 - 8 - 10 to one", but knock out far more planes than the Germans do. Bailed out British pilots are also able to return to the air, but German pilots are lost. Unlike the Dutch and Polish airforce Britain does not "make the mistake of bunching its planes on the runways".
Before the film, several text cards explain bombers and the Royal Air Force chain of command. The film begins with an observation aircraft flying over and dropping a box of undeveloped film. Bomber Command develops the film and analyzes the resulting photographs, which are presented for the audience to see. There has been a massive build-up by German forces in the subject area for the past few months. The film shows the planning of the mission, even detailing how the bomber wing chooses munitions for the task. The weather forecast is expected to be good and the pilots are briefed. The crew of "'F' for Freddie", the bomber that is the focal point of the film, suit up and take off. While over Germany, the crew bombs the target, dead on for one bomb but their aircraft is hit by flak from "faceless" anti-aircraft gunners. The radio operator is hit in the leg and Freddie is the last aircraft to return. Mist covers the water, prompting worry at the Command. Meanwhile, Freddie cannot climb after the flak hit. They are not losing altitude but are in a bad situation. Tension builds in the film until finally, 'F for Freddie' lands. No aircraft are lost and the mission is a complete success.
The plot of the film revolves around the life of seamen on board an anonymous aircraft carrier. Because of war time restrictions, the name of the aircraft carrier was disguised as "the Fighting Lady", although she was later identified as USS Yorktown. A few shots of aircraft landing were filmed aboard the Yorktown's sister ship USS Ticonderoga.