Yoon Ha Lee writes science fiction that often reads like math you can almost feel, and Combustion Hour is a short piece in that lane. The story builds its world fast and trusts the reader to keep up. There are calendrical mechanics, beings of shadow, and a ritual moment the title points at without quite explaining.
The piece is short enough that you can read it twice in one sitting, which is the right way to do it. The first read for the shape, the second for the things you missed.
Lee’s longer Machineries of Empire trilogy is built on similar logic, and readers who enjoyed Ninefox Gambit will recognize the prose rhythm here. For first-time readers, this is a low-cost way to find out if his style is for you.