This is a short science-fiction story in which a woman (who seems to be some sort of black-ops style spy) breaks into a remote secret government facility, possibly (very likely) in a cold snowy setting, like Northern Russia or Siberia or something.
She eventually enters some sort of silo/bunker that she rappels down into and becomes trapped as her climbing gear gets fouled. In this silo are suspended hollow spheres containing miniature people, who seem to be at war with each other. She gets caught up in their battles, which get out of control and eventually she finds her way out.
It turns out the whole thing is some kind of giant automated mechanical machine, for a purpose I cannot remember.