An ex-intelligence officer is offered a job searching for a potential attack on the trans-galactic train network, where he finds a conspiracy that runs deeper than anybody thought.

I’ve read a lot of Timothy Zahn, and he is always easy to read. The dialog is snappy, the aliens convincing, and the characters always have many different motivations tugging at them. Nobody is who they seem to be. That’s always a good thing, as is the mystery that underpins the story. However, at times, he makes the mystery too convoluted, and this is one of those times. The main character, unfortunately, jumps to the correct conclusion way too often, and is guided to the right place at the right time for no reason except to serve the plot, even if some of this is explained by mixed motivations. The end is satisfactory, because the author does his usual good job at tying everything up, though some of it require a rather large stretch. At some points in the book, I thought the author had changed from an earthbound train to a spacebound one after the story had been partially written. Why does a space train need rails? The wheel friction at one lightyear per second must be immense. Some other details make it sound very land-based, as well. Regardless, the technology and characters, not to mention the aliens, were so well-developed that it makes the book interesting, despite its more questionable coincidences.

The book starts out like a film-noir, and I thought the main character was a private investigator. Close, but not quite. He’s an out of luck Intelligence officer who was kicked out of the service for blowing the whistle on a colony that had nothing to offer humanity, even though the government pushed through lies to get colonists there. Yandro turned humanity into an empire, though, and with a trillion dollars (which doesn’t seem all that much in future terms) the Spiders built another Quadrail station which gave humanity status in the galactic network.

The train is the only thing that allows interstellar travel, and it operates like any train service, with transfer stations, side tracks for maintenance, conductors, a bar car, baggage cars, and first through third class coaches. It somehow rolls around on rails, even though it’s moving at a light-year per second. There is a big mystery to it, along with the Spiders, who control the whole thing.

Compton is accosted by a dying man who hands him tickets aboard the Quadrail, which he decides to take, just because of his hunch. He meets the woman Bayta, who drugs him and sends his car to a side branch where he’s told of an impending disaster, which could destroy galactic peace. The Spiders want him to investigate, and he takes the job, thinking it would help in his other job, a secret that he keeps all the way to the end of the book.

He is accosted by Bellidos, Halkas, and other aliens, and each one turns him in the direction of the mystery. While I always enjoy Zahn’s books and storytelling, this one is weak because Compton always jumps to the correct conclusion, even when he’s wrong, because a twist makes it right. He follows two Halkas who he deduces are trying to set him up, and gets captured by the local forces. It turns out that they are, but to get him to do exactly what he does –encounter a rich Halkan who tells them about Modhra II and its underwater crystal caves. It seems that he only tells of Modhra II because Compton pretends to be working for a travel agent looking for new human experiences. What excuse would the Halkan make to get him to go there if he’d faked a different profession?

Bayta, on the other hand, knows all about the plot to get him to Modhra II, but says nothing, because she wants him to figure things out on his own, to avoid drawing attention to a Bellidos and his people, who are trying to destroy the corral that is the real threat. Compton doesn’t believe it, but the corral is an entity that can infect people of all races, and is trying to take over the galaxy. They infect every government, except Earth, so far, halting all investigations into its effects. The Spiders are trying to destroy it before it is too late.

The Spiders and Bayta belong to a race similar to the Mohdri, the corral, but who are incapable of doing evil. They see the Mohdri as the last weapon of their old evil masters. Compton points out that the way they have taken Bayta’s mind is similar to what the Mohdri does to its walkers. But the Chahwyn are willing to let Bayta go, where the Mohdri are not for their followers. Even as Applegate and JhanKla try to convince him that this group mind is better for galactic peace than anything individuals can ever be (Foundation's Edge anyone?), Compton knows that the evil this group mind has undertaken to enforce its will undermines its cause.

Fayr leads the Bellidos and Compton on a raid against Modhra I, which switched names with Modhra II, and is the actual origin of the corral. But Modhri has moved, so their attack with the submarine is too late, though Compton manages to get records showing transactions of corral all over the galaxy. So the Mohdri’s walkers come active, infiltrating the Quadrail and attacking Compton and the others. There is a long fight sequence on the train, which was entertaining but went on a bit long, as Compton tries to get to the baggage car so he can take the hatch and head back to the engine to control the train. The Mohdri’s walkers have been killing the Spiders, another clue to their non-benevolent natures.

Compton comes to the Chahwyn with two secrets –the mystery of the Quadrail, which is the light filament that it follows (not the rails), and the location of the Mohdri. His reasoning is sound, understanding the corral mind as it learned from its mistakes. He blackmails his former employer for a trillion dollars, which he uses to build another Quadrail station at Yondra, a planet with nothing to offer humans, but is the perfect iceworld for the corral to solidify its position.

I wonder if Hardin was in the story just to provide the trillion dollars for the station. It was such a mystery who this man was, and what Compton was doing for him. And in the end, he gets fired and returns to get the money, which was a letdown.

There was a lot of fun technology here, from the Quadrail itself to the scanners and spaceships. As usual with this author, the aliens were distinct and had their own motivations, all of which made perfect sense with the backgrounds he gives them. The characters are realistic and were fun to love and hate. And there is a mystery that is wrapped in other mysteries and intrigues. The only thing that put me off a bit, and made me want to skip ahead a bit were Compton’s flawless intuitions and the coincidences that always took him to the right place at the right time. There was no reason for the Halkas to send him to Mohdra II, especially with the corral controlling them, when they knew he was working for the Spiders. A lot of the logic he uses doesn’t necessarily make sense, though it adds to the plot and solves the mystery in the end.

Nevertheless, the story was fun to read, most of the way through. Even the absurdities, like the trainload of Halkas and other species, or drilling for a submarine, or even tobogganing, were great fun. The story went by quickly, and I think it’s best read over the span of hours or a couple of days. Dragging it out over a week or more allowed some of the less coherent coincidences to drive home. I enjoyed the book enough though to continue with the series, as I have with Zahn’s other books.