The story is set on earth, post alien invasion war, humans mostly enslaved.
The story centers around a group of humans struggling to avoid capture, having to be careful where they go because there's pockets of radiation around. One of the humans is a girl, who I think was called Steelfinder.
The lead male character gets caught and called a rat by the aliens because they dont have a word for human. One of his friends rescues him by shutting off the air conditioning and the aliens who captured him choke to death in the too-dry air.