An 800-page Alastair Reynolds novel compressed into a couple of dozen (excellent) pages. The story starts with a motley crew attempting to obtain the titular object through a raid on a remote property. Their escape route is quite dramatic, taken them to somewhere much, much further away, as the nature of Object Three and its relationship to Object One is revealed.
Teasingly, Cambias takes the reader only so far, leaving the reveal to (hopefully!) another story.