I don't have much energy today, so I'll be brief.
This story is about a mouse named "Rodney" (or "Rodent," depending on whether you take his name from Pippa, or from her father, Dr. Krantor). Dr. Krantor has used "SCIENCE" to increase Rodney's IQ and to give him the ability to speak. Krantor's intent in this was to prove that an intelligent mouse that possessed the ability to speak and reason out loud could navigate a maze faster that an IQ-enhanced mouse that couldn't speak (in Palwick's world, intelligent mice have become pretty commonplace in laboratories). However, as you might guess, this isn't the focus of the story. Rather, it deals with the consequences of giving a mouse self-awareness and the ability to speak, while still treating it like a lab mouse. Essentially, Palwick argues that it is wrong to keep a creature that can speak, reason, and even come to terms with the inevitability of it's own death, in a cage. That, ultimately, self-awareness brings a desire for freedom; a desire to live, and not just to survive. While a normal mouse may be happy with his lot as a lab animal, Rodney desires more.
It's interesting to note that, unlike other stories with intelligent animals, Palwick doesn't seem to fall into the trap of making Rodney anthropomorphic. He isn't a tiny, furry little human. He is clearly still a mouse and desires all the things a regular mouse does. Instead, she focuses directly on the idea of what is would be like to make an animal self-aware; to give them the comparable intelligence of a human being (strangely, he doesn't once try to take over the world).
In all, the story is an interesting read. There is a subplot here as well involving Pippa, Dr. Krantor, and Krantor's ex-wife, but I don't feel that it's all that important to the central theme, and I'm frankly too lazy to explore it right now. All I'll say in closing is that if you come across this story, give it a chance. It's definitely worth a read.