"20504.mp4" sounds like the name of a corrupted file or a piece of "lost media" found on an old hard drive. To develop this into a story, we can lean into the genre, where the video file itself is the catalyst for the plot. The Premise: The Ghost in the Drive
Elias tracks down the original creator of the file, only to find they "erased" themselves from existence in 2004 (matching the "04" in the filename).
: Don't worry about being "cliché" in the first draft—you can refine the unique twists later.