The story begins as a Raymond Chandler pastiche, and follows a private investigator named Clyde Umney as he goes about what he thinks is just another morning in 1930s Los Angeles. He soon discovers that his life as he knows it is falling apart, and is brooding alone in his office when he receives his final client: the crime-fiction author who created him. Through some unknown means, Umney is forced to trade places with the writer and finds himself in the year 1994, where he assumes his new identity but has the goal of returning to his own universe and taking revenge on his creator.
The idea of the writer-as-God would be revisited by King in The Dark Tower series.
"Umney's Last Case" was included as the third installment of TNT's Nightmares & Dreamscapes: From the Stories of Stephen King, starring William H. Macy in a dual role as both Umney and the author. It originally aired on July 19, 2006.