I was all set to start on Dreadnought, the next book in the Clockwork Century series, and saw that this short story actually came next, according to Goodreads. I downloaded it and sped through it in about a half an hour.
The story features two characters who appeared in Clementine, but the story takes place before the events in that book (and in fact even foreshadows some of those events). I'm not sure why this story falls after Clementine in the chronology of the series, especially when this story was also written before Boneshaker. I prefer to read stories in the order they were written, not based on the internal chronology of the series, since there can usually be subtle references to upcoming events if you read them out of order ( see: the Foundation series).
Dr. Smeeks, the senile inventor in the sanatorium, and his assistant Edwin are the main characters here, but this time Edwin is the inventor. He creates a clockwork friend, since as an orphan he has a hard time making friends, but what he assumed would be a machine under his control slowly begins to take on a life of its own. It's ostensibly a horror story, but its setting and feel fit right in with the series so far.
As a horror story, it's not all that satisfying. There's no real sense of why things are happening, as there's no explanation for why events happen the way they do. Not all horror requires it, but here, aside from a spooky prophecy from an inmate at the sanatorium, there's no other hint that the supernatural should happen here. In fact, the way the series has progressed, the supernatural feels out of place all together. Also, the threat felt mild, and I never felt like either of the characters in the story were in dire straits. There certainly was a threat, but it didn't feel severe enough for me to be concerned.
Fans of the series would probably enjoy the story, but it doesn't really add anything to the world of the Clockwork Century. I don't feel like it was a waste of time to read it, but I also feel like I could have skipped it and not suffered for it.