At the outset of WW1 the aeroplane was seen as having little use other than to act as a spotter plane for the cavalry and artillery. But in the space of 6 months - the bloodiest of the war, a group of young pilots transformed the role of the aeroplane into a deadly killing machine that changed the nature of warfare forever. This is the story of those 6 months, centring around Bloody April during which the average life expectancy of a pilot was reduced to just 3 weeks. The film is told though the first hand accounts of the actual pilots, painstakingly documented in Josh Levin's book, On a Wing and a Prayer, and archaeological digs.