Set as a prequel/sequel spin-off to the 2020 fantasy hit, 'Tale of the Nine Tailed 1938' follows the gumiho (nine-tailed fox) Yi Yeon, who becomes unexpectedly involved in an unexpected incident and is thrust back in time to the year 1938 during the Japanese colonial era. There, he struggles to return to the present day where his beloved lives, while crossing paths with old acquaintances including his former mountain spirit brother Yi Rang, the formidable former western mountain spirit Ryu Hong-joo, and Cheon Moo-young, a former guardian spirit turned hostile. In this turbulent period, Yi Yeon must fight ancient forces, protect his loved ones, and alter history without destroying his own future.