Umney's Last Case

It’s just another ordinary day in 1930s Los Angeles for private investigator Clyde Umney, until a new client walks into his office. Umney soon learns that his client is the crime-fiction writer who not only created him, but now needs to switch places with him. An unknown power forces Umney to take on the writer’s identity in the year 1994. Now, Clyde needs to figure out how to get back to his own universe and then take revenge on his creator. (source)