A young Lancaster crew's battles over the skies of Germany in a series of highly-dangerous operations. Every event described in this fictional account actually occurred, often many times. Ploughing through skies pockmarked with the smoke of exploding shells from anti-aircraft guns, and coned by dozens of searchlights, they also faced the bullets and canon shells of night fighters.

A different kind of danger, but sometimes no less deadly, often took place in appalling weather conditions. Caught, for instance, in a massive cumulonimbus cloud their aircraft might be battered by hailstones while being tossed up and down hundreds of feet in vicious convection currents, with ice forming up to six inches thick on the wings, and threatening its ability to remain airborne.