Torrent, I assume?
"hls-mh" in this case is not file extension, but movie title.
This download seems to be corrupted.
Normally, rar compressed file would list: hls-mh.r01, hls-mh.r02, hls-mh.r03......hls-mh.rar
When double clicked on hls-mh.rar file, it'd combine all .r01, r02, etc. into one movie (.avi) file.
You may right click on one of hls-mh (with book stack icon) file, click Properties, and see what it says.
