Zahn has modeled this vaguely on the mystery train novels of Poirot and Marple. Unfortunately, he didn't follow their lead of having people die or weird things happen right away. (And they never get near Rigel.) A fired intelligence agent has just finished taking a job (that we find out about in the last few pages) when he comes across a dead man with a Quadrail pass with his name on it. The Quadrail is how you get around the universe in a lightyear-a-minute. Humans are late to the party and had to colonize a fourth world in order to qualify and then pay a lot for our station. The agent decides to try to work both jobs at the same time. After we find out about the different aliens and some technology, strange things actually start to happen. People do die and there's lots of action. There's an infodump at the end, not by the agent, but by another participant, and then in what should be an epiloque, we find out what the first job is.
This would probably make a good novella.