Besides, considering his peculiarities, Earl Bockman made more sense as an evil alien than as the bumpkin proprietor of a crossroads store and service station in the great Nevada lonesome. This was one of those seemingly impossible things that you intuitively knew were true the moment that you heard them: such as the recent report that none of the members of the hit rap-music group calling itself Sho Cop Ho Busters could read a musical note of music.

She wasn’t going to rush outside and blow Earl’s head off, if only because even in her fear and excitement, she could appreciate the difficulty of explaining this action in a court of law. She did not, in fact, know quite what she was going to do now that she had the shotgun, but she felt better with the weapon in hand.

A crackling noise caused her to spin around and bring up the 12-gauge, but Old Yeller was the source of the sound. The dog had gotten her head stuck in the empty cheese-popcorn bag that Curtis had left on the floor by the co-pilot’s chair.

Polly plucked the cellophane trap off the dog’s head, revealing a foolish grin, a wildly active tongue, and a popcorn-speckled face that she couldn’t easily relate to the determined messenger of alien doom that had labored so ingeniously over the keyboard. She turned to the computer once more, expecting the screen to be blank, but the exhortation to RUM! still burned in white letters on a blue field with five other lines of urgently conveyed information.

Old Yeller swabbed her snout with a propeller-action tongue that cleaned nose to chin to nose again, and Polly decided not to question miracles, not to dismiss the message because of the unlikely nature of the messenger, but to act, God help her, as the situation appeared to require.

And suddenly she realized: “Where’s Curtis?”

The dog pricked her ears and whined.

Carrying the shotgun, Polly went to the door, took a deep breath, as she’d always taken just before she had disembarked, nude, from the flying saucer and had descended the neon stairs in that Las Vegas extravaganza, and she stepped into a prairie night turned as strange as any land reached by rabbit hole.

CURTIS HAMMOND IN COMMANDO MODE, as acutely aware as ever that he’s more poet than warrior, concentrates on silence as he silently eases open the storeroom door, concentrates on stealth as stealthily he enters the store itself, concentrates on not screaming and running in terror as, not screaming and running in terror, he proceeds in a crouch along the first aisle, seeking the false mom of mom-and-pop.

The shelves of merchandise follow the rectangular shape of the store; therefore, the aisles are long, and the displays prevent him from seeing the front windows.

Apparently, prairie folk have little concern for a balanced diet, because no fresh fruits or vegetables seem to be sold here, only a variety of packaged goods. Along the back wall stand glass-door coolers stocked with beer, soft drinks, milk, and fruit juice.

At the end of the first aisle, Curtis hesitates, listening for any sound that might reveal the mom’s position, but this killer seems to be concentrating on silence as assiduously as is Curtis himself.

Finally he leans forward and peers around the corner, past a display of batteries and butane lighters. This end aisle is short, leading directly to the front of the store, which in total offers only three long aisles formed by two islands of tall shelves.

He can see a portion of one dust-filmed window, but to determine if Cass and Polly have both boarded the Fleetwood, he would have to stand. The banks of shelves are taller than he is, which means if the

bad mom is lingering near the front of the store, she won’t see him; nevertheless, he remains in a crouch.

Soon he’ll announce his presence to distract the pair of hunters and thus give the twins a chance to flee. Success, however, depends on choosing exactly the right moment to stand and reveal himself.

Moving past the batteries and the cigarette lighters, Curtis peeks warily into the middle aisle. Deserted.

He continues to the next aisle-end display—razor blades, nail clippers, penknives, regrettably no serious weaponry—and pauses again to listen.

The pooled silence is too deep, immeasurable fathoms beyond a mere stillness, deeper even than a hush. This deathly quiet makes Curtis want to shout just to prove that he remains among the living. A sudden chill on the nape of the neck. Looking behind himself, toward the fearful expectation of a creeping assassin, he almost cries out with relief when he sees that nothing stalks him. Yet.

He leans past packages of razor blades dangling from display hooks, and surveys the aisle nearest the front of the store, spotting the bad mom at once. She stands a few feet inside the open door, staring toward the pumps outside, and as far as he can tell, she’s a ringer for the dead woman tumbled with her husband in the SUV.

More likely than not, these hunters are part of the pack that has been after him since Colorado, although it is possible that they are new to the mission. Because they aren’t traveling in the stolen saddlery truck, aren’t using local transport of any kind, he doubts that they are the two who, posing as cowboys, tracked him to the truck stop on Wednesday night.

Whether new to the hunt or members of the original pack, they are as violent and as dangerous as all the others, not individuals but members of a killing swarm. Their name is legion.

Drawn by activity at the pumps, the bad mom steps closer to the open door, and then moves all the way onto the threshold. She is now as much out of the store as in it, and she’s no longer in a position to catch a glimpse of Curtis from her peripheral vision.

Between Curtis and the front door, on the counter near the cashier’s station, a pistol lies in plain sight. Perhaps either the man or the woman now dead in the SUV had time to draw the handgun from under the counter but not enough time to use it. And the bad pop left it behind when he stepped outside to greet the Fleetwood.

The twins are no less endangered just because the hunter went to them unarmed. These are cruel assassins, as quick as vipers striking, more savage than crocodiles two days past their last good meal. They prefer to kill barehanded, though seldom with anything as prosaic as hands, to wade in the wet of death. The twins’ beauty, kindness, wit, and high spirits will gain them not one split second of additional life if one of these hunters chooses to destroy them.

Gazing at the weapon on the counter, perhaps forty feet away, Curtis recognizes opportunity when he sees it. He doesn’t even need to review his mother’s numerous admonitions about the importance of seizing the moment, but sets out at once along the aisle, toward the cashier’s station, proceeding in a crouch but otherwise as bold as any death-marked fool in battle who sees incoming tracers in the sky and assumes they are fireworks celebrating his impending triumph. He is halfway to the cash register when he wonders if he has mistaken bait for opportunity.

The bad mom could step backward off the threshold, whip toward him, and peel him like an orange before he could say Oh, Lord.

Curtis is undaunted, however, because he is Roy Rogers without the singing, Indiana Jones without the fedora, James Bond without the shaken martini, steeped in heroism as defined in 9,658 films enjoyed over two days of an intense three-week cultural-preparation program, all 9,658 viewed by direct-to-brain megadata downloading prior to planetfall. In truth, he has been made just a smidgin crazy by all those movies, which he hasn’t quite yet assimilated, and he isn’t at all times able to sort out the truth from the fiction in what he has seen on his mental silver screen. But because movies have inspired in him such a glorious sense of freedom and such a passion for this strange world, he happily accepts the consequences of a temporary mental imbalance if that is the necessary price for those two days of unparalleled entertainment, education, and uplift.

Indeed, the examples set by film heroes prove to be what he needs, because he reaches the cashier’s station and rises to his full height without alerting the bad mom. She still stands in the doorway, costumed in the dead woman’s clothes, facing the pumps.

The window behind the cashier’s station is clouded by dust, but Curtis can see the Fleetwood. Cass leans against it, facing the bad pop, and appears not to have been alerted to their danger.

Two minutes have passed since Polly received the message through the dog. She no doubt will act soon. The time has come for Curtis to provide the necessary distraction.

When he picks up the pistol from the counter, he notices beside it a paperback romance by Gabby’s favorite novelist, Nora Roberts. Evidently, everyone reads her, but he assumes that this copy belongs to one of the dead people out back rather than to one of the killers, and that Ms. Roberts’s popularity is not yet multiplanetary.

The external safety on the pistol isn’t engaged. He holds the weapon with his right hand, steadies his right with his left, and dares to inch toward the. open door, angling for a clearer shot.

The killer remains unaware of him.

Nine feet from the door. Eight feet.

He halts. This line of fire is ideal.

Standing with feet apart for maximum balance, his right foot ahead of the left, leaning forward from the waist to prepare for the recoil, he hesitates because the target in the doorway looks so much like an ordinary woman, appears so vulnerable. Curtis is ninety-nine percent certain that she is only slightly less vulnerable than an armored tank and that she’s not a woman at all, let alone an ordinary one, yet he can’t quite bring himself to apply the final increment of killing pressure to the trigger.

That one percent of doubt inhibits him, though his mother always said that nothing in this life is absolutely certain and that refusal to act on anything less than a hundred percent certainty is in fact an act of moral cowardice, an excuse never to take a stand. He thinks of Cass and Polly, and lost in a vast wasteland of one percent doubt, he wonders if the dead woman in the SUV might have an identical twin who stands now before him. This worry is ridiculous, considering the off-world transport disguised as a Corvette, considering the broken-necked victims. Yet the boy stands in this purgatory of indecision because although he is his mother’s son and although, in her company, he has endured heated battles and has seen terrible violence, he’s never before killed, has trained with various weapons but has never fired upon another creature, and here in this small crossroads store, he discovers that killing, even for heroic purpose, is harder than his mother warned him that it could be and much harder than ever it appears to be in movies.

Alerted by scent or by intuition, the woman in the open doorway turns her head so quickly, so sharply that a snap should be audible, and on sight she knows Curtis. Her eyes flare wide, as any startled woman’s would, and she raises one hand defensively as though to ward off bullets, as any frightened woman might, but in the same instant, she is betrayed by her smile, which is as inappropriate here as would be a sudden burst of song: a predatory smile of serpent cracking wide to swallow mouse, of leopard poised to make a deadly pounce.

In the telling moment, when you either have the right stuff or you don’t, Curtis discovers he has it, and in abundance. He squeezes the trigger once, twice, rocked by the recoils, and he neither falls back in the face of the assassin’s fierce shriek nor merely holds his ground, but takes a step forward and fires again, again, again.

Any fear that this woman might be the legitimate twin of the one lying dead in the SUV is put to rest even as the first round from the pistol shreds through her torso. Although the human form serves well the wars of this world, it isn’t the ideal physiology for a warrior species, and even before the first bullet leaves the barrel, the bad mom begins to morph into something that Curtis would rather not have seen this soon after consuming an entire large bag of cheese popcorn washed down with Orange Crush.

In the first instant, the killer launches itself at him, but it is mortal, not supernatural, and though its rage would drive it into the teeth of death, its cunning overcomes blind fury. Even in the act of springing at Curtis, it kicks off the corner of the cashier’s station and launches itself in a new trajectory, toward the tall shelves of packaged goods.

Of the four additional shots that Curtis fires, three find their mark, jolting the shrieking assassin, which scrambles quickly up the shelves as an acrobat might swarm a ladder with leaps and flourishes. Hampered by a cascade of cans and bottles and boxes, the killer is in fact scaling an avalanche, yet it blitzes past all tumbling obstacles to reach the summit even as the fourth shot strikes and the fifth misses.

During this lightning swift ascent, the killer morphs toward more than a single shape, simultaneously sampling a menagerie of murderous species, bristling with talons and beaks, with horns and spikes and scapulae. Hands grasp, pedipalpi quiver, spiracles ripple, pincers snap like scissors, and other ill-defined extrusions appear and at once vanish in a roiling tumult of glistening carapaces that melt into whipping tails, in snarls of coarse hair that smooth into scaly flanks, expressing a biological chaos that makes Curtis’s confusion in the twins’ bathroom seem, by comparison, merely an amusing faux pas. Clinging for but a fraction of a second to the crest of the shelves, hunched under the fluorescent lights, all shapes and none, and every shape a lie, the churning beast might be the Beast himself, recognizable to the poet Milton as the ruling prince of the “darkness visible” in Hell—and then it’s gone into the next aisle.

Although mortal, the assassin will not die as easily as Curtis would have perished if it had reached him. The spirit of every evil is resilient, and in this case, so is its flesh. Its wounds won’t heal miraculously, but those it has might not be sufficient to put it down permanently.

Curtis is loath to turn his back on this crippled but dangerous adversary; however, Cass and Polly are outside with the second killer and helpless against its savagery. With at most five rounds left in the pistol, he’s committed to further distracting the remaining assassin in order to give the twins a chance to flee.

Frantic, clambering across the treacherously shifting drift of merchandise that has crashed from shelves to floor, he makes his way to the open door, praying that his two beautiful benefactors, glass-shod Cinderellas, fragile flowers of Indiana, will not have their kindness to him repaid by bloody death.

WHILE DIESEL FUEL FED the hungry belly of the Fleetwood, Earl Bockman droned on about the varieties of packaged macaroni dishes, frozen and not, that he and Maureen stocked in the store. He held forth not in the tone and manner of a merchant trying to drum up a few bucks’ worth of business, but with the chatty enthusiasm of a pathetic social misfit who believed that sparkling conversation could be made from any subject short of the raw lists of names in the telephone directory, although perhaps he would get around to those, as well, before the cap was back on the tank.

If Cass had been a criminal type or a rabid activist committed to the elimination of sound pollution, she might have shot Earl and put an end to her misery and his. Instead, she watched the gallons mount up in the tabulation windows on the antique pump and thanked God that she had developed such a high tolerance for boredom during her childhood and adolescence in rural Indiana and in a family whose friends were all college academics.