Though it's evident that Wilson would like for it to be more, Mysterium is a novel best enjoyed as pure escapism with some clever speculative window dressing. It's Stephen King with some cosmology thrown in, and despite Wilson's penchant for tossing in one familiar (I'd hesitate to use a word as loaded as "hackneyed" here, because Wilson does have a talent for owning his clichés) story element after another, the novel delivers solid suspense and action even as it comes up short on characterization and throws around plot contrivances with abandon.
The prologue sets the story up with an impressive sense of urgency and, yes, mystery that does justice to the title. When an artifact of inexplicable origin and construction is unearthed at an otherwise unimpressive Turkish archaeological dig, it is shipped off to a hastily constructed and top-secret government laboratory located just near the quintessential Small American Town of Two Rivers, Michigan — where it promptly blows up. Residents of Two Rivers awaken the following morning to discover that their town, the nearby lab, and a sizable chunk of Michigan has been transported...elsewhere.
That "elsewhere" turns out to be an alternate Earth, in an alternate universe. And on this Earth, America is run by a fascist regime of polytheistic Gnostic Christians so violent and oppressive they make Stalin on a bad day look like Little Lord Fauntleroy. Quickly, troops move in and occupy Two Rivers, led by frightening commanders known as Proctors and Censeurs. Martial law is instituted, food is rationed, and people are shot dead for the slightest resistance. And oddly, Wilson rushes through this section of the story, referring to the atrocities of this strange army only in frightened conversations and flashbacks. To say that Wilson missed a golden dramatic opportunity by not depicting the actual occupation of Two Rivers in detail and letting us experience the terror and oppression of the townspeople firsthand is an understatement.
This alternate-America is about half-a-century or so behind our own in technology, and so when the Two Rivers library is cleaned out by the Proctors, very soon the evil leaders have the knowledge they need to build a weapon that has been eluding them for years in their war in central America: an atomic bomb. And, once the bomb is built, what better place to test it than this creepy town that has dropped out of the sky so inexplicably, and which is giving the fanatically religious leaders of this alternate-America absolute fits?
The story moves very briskly, never letting you dwell to long on Wilson's use of contrivances and "author's convenience," and the tension is at times quite palpable. Among Wilson's characters, it is of course the townspeople who are the most sympathetic. Dexter Graham is an unhappy schoolteacher still guilt-ridden over the death of his family years ago, who finds himself thrust into a position where life, something he had nearly given up on, becomes a precious thing to fight for. Howard Poole is a young scientist who is the nephew of the researcher responsible for bringing the artifact to Two Rivers in the first place. Like the protagonist of a thousand Hollywood movies, he must overcome self-doubt and cowardice to emerge an unlikely hero. And Clifford Stockton is a 12-year-old boy who fills out the very Stephen Kingish role of the spunky and rebellious child who defies evil.
Wilson fares less well with the characters populating this nightmarish alternate world. Villians like Clement Delafleur seem like movie Nazis. Every time he was on the page I was reminded of Conrad Viedt as Major Strasser in Casablanca. Most of the other Proctors and government baddies struck me the same way, hissably evil but in a very caricaturish, Hollywood style. Some of these alternate-Americans are good folks, of course, but even their characterizations are perfunctory. Linneth Stone, a sociologist brought in to evaluate the residents of Two Rivers, takes up with Dexter Graham and switches her loyalties to the townspeople so quickly and effortlessly that it's clear Wilson only added her to the story for this purpose. Milos Fabrikant, a scientist who actually builds the bomb that threatens the town, is wracked with guilt over what he is doing, but in an obligatory way. He appears very little in the novel and we never get enough of his background to understand the depth of his inner turmoil.
Despite these few shortcomings, the novel admirably compensates with some tremendous action scenes and a final, race-against-the-clock fifty pages that are often breathlessly exciting. And the climax is something else. The explanation Wilson offers up for the curious artifact that started all this brings up age-old quasi-religious cosmological questions, but Wilson never lets his themes degenerate into mumbo-jumbo, and the end result is satisfying in the novel's context, if not as profound as it wants to be. On a purely superficial level, this is a terrific suspense yarn. Beneath the surface, there are imperfections, but then I suppose, in that regard, Mysterium has quite a lot in common with this universe of ours after all.