The film and the novel on which it was based follow the same basic plot, but many details were changed for the film. Some scenes were re-arranged in sequence and the story was heavily condensed with most of the characters' backgrounds not mentioned. The first half of the book sees the squadron equipped with Douglas Boston light bombers before converting to the Mosquito. An early coastal shipping strike sequence was omitted for the film, as was an action packed reconnaissance mission. The film adapts only the second half of the novel.