In the kingdom of Aquilonia, a year of peace for King Conan and his new queen Zenobia is broken when the latter is abducted by a demon. Conan learns from the wizard Pelias of Koth that the eastern sorcerer Yah Chieng of Khitai is responsible, and begins a quest to recover her, little realizing that the fate of the world as well as Aquilonia rests on the outcome of the contest.
Chronologically, The Return of Conan falls between Howard's novel The Hour of the Dragon (also known as Conan the Conqueror), and the four short stories collected as Conan of Aquilonia.
The Hyborian Age, Part 2
The second part of Howard's essay detailing the pseudohistorical prehistory in which the Conan stories are set describes the period from Conan's day through the end of Hyborian era and beyond.
References
Laughlin, Charlotte; Daniel J. H. Levack (1983). De Camp: An L. Sprague de Camp Bibliography. San Francisco: Underwood/Miller. pp. 85–86.