Philip Stenning is a commercial pilot, trained during the First World War. After his engine fails, he crashes and is rescued by an escaped convict, Denis Compton, who turns out to have been framed for embezzlement by his Italian half-brother, Baron Rodrigo Mattani, who is smuggling drugs into England.

The story tells how Stenning plays a key role in breaking that drug ring. It involves episodes characteristic of Shute: flying, small boat sailing, and a love story.