The start of Dreamcatcher finds our four protagonists - Jonesy, Henry, Pete, and Beaver - at crucial crossroads in their lives. All possess some sort of low-level psychic ability (clairvoyance and rudimentary telepathy, weaker forms of the abilities Johnny Smith utilized in The Dead Zone), and all are suffering. Beaver is loveless and unhappy, Pete is an alcoholic, Henry is suicidal, and Jonesy is about to be hit by a car, shattering his hip and changing his life for the worse. Interestingly, we meet these four separately, and while their stories are concurrent in Dreamcatcher, we mostly follow them separately, as well. Only intermittently do we see two of them in the same "present" scenes, and never more than that. This structure contrasts with what we come to know about them as children - when they were inseparable best friends - and the fact that they meet once a year at a cabin the northern Maine woods to go hunting. In other words, we are told that they are close, lifelong friends, and shown that they are divided. This subtle technique is one of Dreamcatcher's most powerful assets.
Gradually, the central theme of the novel emerges: how childhood heroics affect the people those children become as adults. It is with this theme that we first consider Dreamcatcher a counterpoint to King's epic novel It, a connection that grows deeper and more literal as the novel progresses. In 1958, the Losers Club battle It to stop It from murdering Derry's children. Their memories of these events supernaturally repressed, they go on to be wildly (and idiosyncratically) successful adults; It's extended metaphor for grownups losing touch with childhood is one of its central conceits. In Dreamcatcher, the four friends rescue a young Down's syndrome sufferer, Douglas "Duddits" Clavell, from bullies, an act that reverberates through the novel and casts a dark shadow on their adult lives. On more than one occasion, a character comments that saving Duddits was their finest hour. Not given the luxury of forgetting that the Losers Club was afforded, they have spent lifetimes unable to live up to the purity and kindness of who they were when they were young.
In ways, the more scatological elements of Dreamcatcher tie it to It as well. Sewers, toilets, and the occasional outhouse were essential structural elements to King's earlier book, there as here underlining the "gross-out" form of revulsion King occasionally attempts in lieu of terror or horror. The "gross-out" parts of Dreamcatcher oddly serve a metaphorical function, too. Front-loaded into the book with our initial impressions of the four friends, we can see the focus on bodily function as a commentary on the way men behave when alone together. Only by delving deeper into the novel - and the characters - do we get beyond these surface elements.
More literally, King positions the town of Derry as a focal point in Dreamcatcher. We come to learn that Duddits still lives there; as a Down's sufferer, he is stuck in perpetual childhood, neatly contrasting the lives of Jonesy, Pete, Henry, and Beaver, as well as strengthening the thematic connections to It. When Jonesy returns to Derry late in the novel, King makes his connections to It explicit, by directly referencing both the destruction of the Standpipe and the seven members of the Losers Club. The time frames focusing on these four as children and adults are interpolated with those in It, as well: It is still alive and affecting (if not awake and actively feeding on) Derry in 1979, when the four save Duddits, and has been dead for sixteen years when we see them as grownups in 2001. Underlining the contrast between Dreamcatcher and It, King tells the "past" sequences in the present tense, just as he had written the introductory "present" portions of "June of 1958" and "July of 1958" in It. Chillingly, a spray-painted sign on the new marker for the Derry Standpipe reads PENNYWISE LIVES. While certain late elements in Dreamcatcher seem to indicate that the invading aliens mimic some of It's abilities, there is no further mention of It or Pennywise. However, the message does lend credence to the idea that other like creatures (such as Insomnia's Kingfisher or "The Library Policeman"'s Ardelia Lortz) might be part of a larger race connected to It, or that some of It's children survived Ben Hanscom's boots.
The aliens appearing in Dreamcatcher are of a different sort than King has approached before. In both It and The Tommyknockers, the malevolent extraterrestrial forces have existed on Earth (both, intriguingly, underground) for centuries. In Dreamcatcher, we follow an invasion of sorts, happening now. The aliens are threefold: humanoid creatures recalling the Whitney Streiber Communion-type, known by the military as "grayboys." An internal life-form, called alternately "byrum," "implants," or "shit-weasels" are brainless, snake-like creatures that interact disastrously with terrestrial creatures, gestating inside them, growing too large, and then eating their way out. (Recalling the chest-busters in the Alien films, it is the shit-weasels we first encounter; the gory opening chapters feature a particularly nasty specimen that eventually kills Beaver.) Additionally, a substance known as either "ripley" (another reference to Alien) or "byrus," grows in the form of a red mold or fungus - the byrus, left to propagate inside an infected person, eventually begets byrum, the shit-weasels. King insinuates that the byrum's/byrus's intended hosts live in mutual symbiosis with the fungus and the weasels, perhaps being what allows them to communicate telepathically. (King further hints that the life-cycle may go beyond symbiosis, and that when the grayboys die, they decompose into byrus; though Dreamcatcher is a horror novel working within science fiction trappings, this is a very compelling science fiction construct.)
Early in the novel, Jonesy is uniquely affected by the byrus: instead of being infected with the red growth or the implants, he is, in a way, possessed. An alien presence he comes to think of as Mr. Gray inhabits him, attempting to use him to carry out its mission to infect a town water supply with the byrus, eventually conquering the planet with it. Perhaps due to his unique nature, Jonesy is able to prevent himself from being taken over completely, using a device King first utilized in The Regulators and would revisit in Song of Susannah: creating an invented room within his mind where his essence still exists. Here as in those other novels, this is an odd, almost metaphysical concept, yet King writes it in a way that it is easy to grasp, remaining intriguing at the same time it is accessible and even fun.
The problem for the byrus and byrum on this planet, especially during winter, is that the environment is hostile - the growth can't take hold. The problem for the grayboys is the military, especially a violent, potentially insane colonel named Abraham Kurtz, who orders the wholesale slaughter of the surviving grayboys ... as well as the humans who had been infected by the byrus.
Kurtz is, unfortunately, one of Dreamcatcher's weak spots. Like the later Big Jim Rennie (Under the Dome), Kurtz is put in charge of an isolated situation and sets about immediately abusing his power, to similar results. King's treatment of Kurtz is not subtle. At one point, he bombastically punishes (and critically injures) someone under his command for making a racial epithet, yet in the following pages makes one of his own (recalling Buddy Repperton in Christine, who does something similar moments before his death). His second-in-command, a man named Owen Underhill, opposes the murder of the grayboys and instantly becomes his enemy. Later, when Underhill helps Henry escape from Kurtz on a mission to stop Mr. Gray/Joensy, Kurtz grows almost comically obsessed with catching up to Underhill and murdering him. (Underhill, a far more interesting character, fits very neatly into the novel's overarching theme. In part to atone for a perverse act he committed as a child, he helps Henry and attempts to save the world from Mr. Gray. Interestingly, as Henry, Jonesy, Beaver, and Pete have lived their lives in the shadow of the good they had done as children, Owen Underhill lives in the shadow of the bad. King here - as elsewhere, especially in It - seems to be saying that the acts we commit as children, good and evil, are epic, holding sway over the rest of our lives.)
As Henry and Underhill (and later, Duddits himself) follow Mr. Gray's slow progress from Maine to Massachusetts, Kurtz follows them. This allusive journey is fascinating, bringing to mind Joseph Conrad's Heart of Darkness and the film Apocalypse Now, albeit in reverse. King, however, feels it necessary to directly reference these two works, as well as baldly state that Kurtz appropriated his name at some point. Like Jessie's explanatory letter at the end of Gerald's Game, King allows the threads of the novel show too clearly in these instances. Further, in addition to the later Big Jim Rennie, Kurtz resembles Norman Daniels in Rose Madder. While Norman begins that book as a genuine menace, he grows almost laughable by the end. Kurtz never quite grows as silly as Norman, but his outsized presence and crumbling sanity make him hard to take seriously in parts.
Additionally, while not necessarily a flaw, a late-novel concept throws much of the rest of the book into question. Jonesy "discovers" that the being he knows as Mr. Gray was not actually one of the grayboys; more importantly, he insists that the grayboys don't actually exist as he and the military had seen them early in the book. Very late in the novel, King hints that the ship that came to earth carried only the byrus, and that the original owners of the craft were missing or dead. While this brings up some interesting points - most importantly that forms of the byrus works similarly to It, in that it reads the minds of people and takes its physical shape from their minds - it seems to contradict earlier descriptions of the grayboys. King seems to intend this as a major revelation, but it doesn't impact the outcome of the novel at all. The concept is confusing and vaguely explained.
These issues aside, Dreamcatcher is a powerful novel. While concepts are borrowed from other books (notably It), King uses them here to tell a unique and uniquely pessimistic story. Duddits, the latest in a line of King's mentally-challenged characters (including Tom Cullen from The Stand and John Coffey from The Green Mile), is sympathetically portrayed and, at least in his early scenes, one of the few bright spots in a dark novel. King's first novel of the 2000s, Dreamcatcher is equally compelling and bleak, pointing toward later books (Black House, Cell, and Full Dark, No Stars among them) similarly unafraid to tell unnerving stories with little hope of happy resolutions.