Destroying the Earth was the climax of Nylund's previous book, Signal to Noise, and as much as he tries in this second installment, it's hard to beat that for an encore. In the first book, cryptographic genius Jack Potter had learned how to use the interstellar vibrations of a super-heavy isotope to communicate with Wheeler, an alien "businessman" that makes Quark the Ferengi look like Mother Theresa.

Now, as A Signal Shattered opens, Jack has taken refuge on the moon and is wondering what to do next.

At first, he doesn't do much. The first third of the book consists of Jack dithering, trying to get supplies, surviving sabotage attempts by other survivors, trying to cut deals with a couple of former business associates who are hanging out in other star systems, trying to reprogram the teleport gateway that saved his butt, and occasionally announcing he feels bad about causing the death of eleven billion people.

There's a lot of "trying" and not much "doing" here, and it's not until around page 175 he finally gets off square one and starts teleporting around the galaxy. Even then, the action is limited to bopping around space, dithering some more, evolving into a parallel-processing superhuman intellect, and having a big showdown with Wheeler. It's all strangely unexciting.

It's been a while since I've read a pro novel that so completely failed to engage me on any level. Nylund includes lots of action scenes and more wondertech than you can shake a stick at, but it's all arbitrary. There's no speculation involved, no sense of "could the world really be like this?" -- it's just props and special effects.

What's worse is that the same is true of the characters.

We'll skip the supporting characters; they're such ciphers it's not worth the bother. The gaping void at the center of this book is Jack.

Jack is oddly directionless. He sits around for pages at a time, clueless, then suddenly gets a hunch that rachets the plot forward a notch. There's no deduction or reasoning involved. It's more like Nylund has gotten tired of the scene, so Jack gets a hunch and goes to the next plot point.

Jack is also surprisingly unconcerned with the effects of the teleport gateway, which steals rotational energy from planetary bodies, usually in dangerously large quantities. The gateway nearly wrecked Earth before Wheeler finished the job, but while its abuse is something Jack supposedly feels guilty about, most of the time he keeps on bouncing around the cosmos, smashing planets with gay abandon.

And that's the way it goes. If it moves us along to the next scene, Jack thinks or feels it. If it doesn't, he doesn't. There are a few exceptions -- early on Jack shows a flicker of character and wishes he were a superscience hero, because they always know what to do. Later on, I was wishing he was a superscience hero too -- those strong-jawed manly men had more of an inner life.

Maybe all Flash Gordon wanted to do was save Earth and win Dale Arden's heart, but at least his motivations, combined with Ming's, drove the plot. In this book, it's the other way around: whatever the plot needs at the moment, Jack wants.

It's also significant that even though Jack regularly broadcasts his emotions as virtual reality symbols, Nylund needs to interpret them all for us. There's just not enough to Jack for us to figure out what he's thinking on our own.

In the end, we're left with action-movie science fiction. It's Bruce and Arnold, lots of explosions, millions for high concept and not a penny for personality. And while I'm not knocking action movies -- they're great in a dark theatre with plenty of popcorn and your brain in neutral -- I expect more than that from a book. A Signal Shattered is just noise.

Chris Aylott is co-owner of The Space-Crime Continuum, a science fiction and mystery bookstore in Northampton, MA.