The opposite of the plague starts in a plaza in Prague. For two days, unexplained disembodied lights of increasing intensity assemble in the air above the monumental Jan Hus Memorial, yellow and gold lights with no discernible origin or power source. The phenomenon continues for long enough that scientific researchers manage to assemble in the square and devote some time to trying to figure out what's happening.
They could have figured out that the lights were originating from another dimension, but that would have taken another full year. Scientific research just takes that long sometimes. What matters is that by the time a night and a day have passed, the lights are propagating; identical phenomena are starting in Times Square, Red Square, Piccadilly Circus. The lights are growing in number and intensity, like a slowly approaching constellation seen through nebulous fog. And after another night and a day, the first of what are now more than seventy red and gold and orange lights condenses out into the form of a tremendously tall humanoid, and steps down from the air, and walks on the ground.
The figure is around fifty percent taller than a typical human, lean and beautiful though not obviously male or female. They have long, shining hair and wear robes of luminous red and gold, like portals cut through to some other, brighter dimension. They are barefoot. The paving slabs making the square up cook beneath their feet. They are brilliant and hot and difficult to look at directly. They have a benevolent smile.
They turn and extend a hand in the direction of another of the lights, which likewise crystallises out, become a different, slightly shorter figure, though still grand in scale compared to any human, three metres tall or more, and similarly attired. This one is more obviously female, and behind her a third figure follows, a younger-looking man, with a vague familial resemblence to the other two, their son, perhaps.
It is evening and the sky is that deep aquatic blue, the colour it only takes on briefly on the clearest evenings. There's a crisp wind and autumn leaves whipping through the square. The three figures stand there, soaking up atmosphere and taking in the scene around them, for some time — the Baroque architecture looking down on them and the feeble little humans looking up, cameras in hand.
The tallest one bends down, to take a look at the person who is closest to them, a shortish, oldish Czech lady with a heavy magenta coat, a hand-knit scarf and an unconvinced expression. The golden person's facial features are more narrow and angular than most humans', with a smaller jaw and higher cheekbones and, though it's not immediately clear from the front or through their mountain of luxurious hair, a cranium which extends back further than most humans' do, accommodating a substantial brain. The golden person holds a hand out, fingers extended forward and palm upturned, offering to take the Czech lady's hand. She films the hand and the figure's face, but otherwise doesn't move.
The figure rises to their full height again, smiling benevolently at her, and then at everybody. There are news crews filming this too, now.
There is a kind of pressure building in the square.
The figure turns to their family and says a few words in a soft, deep, rich language. The language is dense and meticulous, with layers of expressive detail, like a fine tapestry. Those in the crowd who can hear it do not comprehend it, but feel a stab of envy — no human language sounds so beautiful, or works so well.
As this is happening, more of the visitors are condensing out of the air, here and all over the world, and not just in public squares, in lesser-known locations where fewer humans are around to greet them, and here and there in deep wilderness and desert.
The female gently indicates that their companion should move aside. She takes their place and kneels this time, bringing her head down level with the Czech lady, who has become anxious and disturbed now, for reasons she doesn't fully understand. The Czech woman turns away, not able to look any longer. "I don't like this. I don't like them," she says to those she passes as she retreats. "We should make them go away."
Someone else takes her place, a younger, shorter woman with wilder hair and a much better camera. The female visitor holds her great hand out, and says a sentence in her golden language. The sentence's true meaning is a totally unobjectionable, neutral greeting, but something about the way it's spoken flips a kind of switch in the ears of those listening. A dial swivels from ambivalence to irritation to furious envy to simple, unthinking, hivelike fury. The mood in the square shifts, and the woman with the camera throws it aside, and as it swings from the strap around her neck, she lunges forward, takes the visitor's hand, and sinks her teeth into the flesh between her index finger and thumb.
It is just plain flesh. As extraordinary, tall and beautiful as the visitors are, they are conventional flesh and — as is clearly visible on camera now — blood. The visitor recoils, emitting a shriek of pain and pushing her attacker back into the crowd. The crowd is getting the idea now, though.
It's not clear which of the visitors shouts, or what they shout, but their meaning is clear: "Retreat!"
Within another few moments, the square is cleared. The luminous visitors have folded back up into their nebulous light form, though they have not actually winked out, the way they came. People roam the square, snatching at the out-of-reach lights, throwing cobblestones at them, to no effect. Most of the people in the square aren't fully conscious anymore, though a few are. Everybody in the square, though, no matter how clearly they're thinking, wants the visitors to go away.
After the news is broadcast, the feeling spreads. In some places, it spreads without the news itself actually being shared. A primal, hateful memory has stirred. Before another night has passed, the feeling is shared by everybody in the world, a stabbing, urgent need to chew these golden visitors into pieces.
Back on the ship:
"I don't fully comprehend it," Olaea says. She winces, more with unfamiliarity than with discomfort, as their vessel's ambient medical field cleans her wound out and rapidly repairs it. In a second her skin is perfectly healthy again. "What were those things?"
Her spouse shakes their head. "I, too, find it difficult to comprehend. Since the birth of human civilisation, tens of thousands of years ago, we have blossomed into a cathedral of pan-galactic unity and peace. We have discovered innumerable planets across all of the galaxy which support our families, as well as establishing habitats on innumerable more less habitable planets, and in conventional space, and in deep, starless depths, and even in the interdimensional spaces. There are places where we cannot live without mild adaptation... but we have never encountered a world with pre-existing life, let alone life so closely resembling us, let alone life which was actively hostile to our presence in such a manner. Could we have done something wrong?"
"I don't believe any of us made an aggressive act," Olaea says. "Could it be that our very presence was threatening to them, our presentation? Descending bodily, haloed in light, from our extradimensional home, was perhaps frightening to them."
Their son is studying the ship's logs. "It appears that the family in our sister ship, the Nacrynes, took a few of the creatures back onto their ship for examination. They are behaving with great and mindless hostility."
Olaea asks her spouse, "Why this planet? You led us here, to this specific planet, Kvenn. On the journey here, it seemed that you were following some instinct. You regularly consulted a private file which you declined to share with us. Did you know what would happen when we came here?"
Kvenn considers the matter before speaking. "Human civilisation is tens of thousands of years old, but that is fantastically young by astronomical standards. We have not existed forever. We originated somewhere. I have been performing historical and archaeological research, backtracking the the locations of the earliest human settlements, in an effort to learn our true origins. During my studies, I discovered exceptionally obscure and cryptic references to a particular, minuscule, insignificant region of space which had been declared as off-limits by the ancient Gliesians. My research indicated that there were numerous star systems in this distant region which had been overlooked for settlement. As you know, upon arriving in this system, which is the seventieth of the systems we examined, I observed that one planet was naturally habitable for human existence, requiring even less terraforming than even the best-fitting planets we have ever found. This seemed like a logical place to land."
The son, Yui, says, "You believe this planet is where the human species originated?"
"I do. There are legends that a tremendous disaster befell the earliest humans, forcing us into the stars."
"I know those legends," Yui says. "...Honoured parent, I am receiving a signal of distress from the Nacrynes' ship. It would appear that they have been unable to control the animals they brought aboard. Or their ship! They are reporting being overrun. They have lost control!"
Yui barely has time to finish the sentence before the Nacrynes' ship collides with their own. Safety technology being as advanced as it is now, the collision is as devastating as it is harmless — an explosion, devastation, instruments and hull wrecked, and then everything suddenly falls silent, as the two ships' hulls naturally knit themselves together into a single perfectly viable, if misformed, ship. The second ship comes to rest with its bridge lodged at a jaunty angle through that of Yui, Kvenn and Olaea's ship.
"I assume that everybody is unharmed," Olaea says, in a similar tone to that she would use to offer all present tea.
"I don't see how anybody could possibly have been harmed," Kvenn says. He looks up into the Nacrynes' ship's bridge, which is sideways, gravity and all. "Hullin? Vez? Are you well?"
Hullin peeps over the edge. Hullin looks a little the worse for wear. Same golden garments as the rest, but his hair has become dirtier and darker. His skin is shining less, turning a dirty white, and his eyes are wild and blue. And there is blood gushing from a wound in his skull.
"Hullin, my friend! You look a fright. What happened with these animals? Your ship should have healed you."
"The animals are disposed of," Hullin says. "We jettisoned them into the golden void, once it became obvious that they were too hostile to contain ourselves."
"Jettisoned? Hullin, my friend, you should have returned them to their point of origin! You are likely to have damaged their societal integrity. They may be animals, but—"
"Furthermore," Hullin says, "they were hungry. Hungry for something which Vez and I were unable to provide them. For... brains."
Kvenn dares not ask another question. At that instant, Vez gets up, clearly dizzy. "What happened?"
"Brains!" Hullin declares, falling upon his spouse and biting with tremendous force into the bridge of their nose.
"Great void!" Olaea shrieks. "Hullin, what has become of you?"
"Some kind of vile hunger!" Hullin declares, mouth filled with Vez's flesh. "A virulent, savage need for cerebral flesh."
"And I also," Vez screams. "The same hunger." They get to their feet, unsteadily, missing a vast chunk of their face. Hullin chews and swallows. The two of them, now aligned in motivation, and looking more and more like the dirty, filthy animals of "Earth" with every minute, turn their heads to the watching family.
But Kvenn, Olaea and Yui have already bundled themselves into the escape pod, and left the ship behind.
"I remember now," Kvenn says, pacing about the narrow, if comfortable, space. The pod is barely less spacious than the main part of their interdimensional ship. "There were ancient riddles and legends of curses. A kind of plague broke out, which reduced humans to a base state, where higher achievements of interdimensional divination and oneness fell aside. A kind of secondary human arose, a mindless, violent, crazed animal. The contagion was so powerful and difficult to contain that it motivated the birth of interdimensional travel."
"The legends were that specific?" Yui asks.
"There are hundreds of different legends with the same approximate pattern," Kvenn says. "Among anthropologists it was assumed that each legend was simply the result of fighting off some infectious disease, in the same way that there are hundreds of different flood myths, hundreds of different myths about snakes, or tsunamis, or volcanic eruptions. I doubt anybody imagined they could all have a common origin. A disease of the brain!"
The escape pod rocks from side to side, streaming through interdimensional space, then emits a few calming bleeps to indicate that it is undergoing re-entry into physical reality, and that it has come to rest on the nearest safe piece of terrain.
"How infectious?" Olaea asks. "How contagious?"
"I believe we have reached a safe harbour," Kvenn says. They crack the pod's door open and steps out. The pod has landed on a hill, on the edge of a thick forest. Below it, there are the lights of a little town. The pod casts a blinding golden light, visible for miles around. There is movement in the town. People are looking out of doors. Seeing the pod. Starting to set out, to climb the hill. "Ah... then perhaps... We should move further into the forest. Or at least... arm ourselves."
"And this world, these cities," Olaea asks, "they are what? The civilisation that these diseased protohumans built? After every single one of them was infected with this disease of the brain, they built all of this? How?"
"I feel discussions may have to wait for later," Kvenn announces.
"May we use the projectile weapons?" Yui asks. He is, for all his maturity, in many ways still a boy.
"We may have no choice. Arm yourself and your mother," Kvenn says. They look at their glowing skin, and clothing, and hair. "Ah. Eluding these... automata... may be challenging."
Olaea gets up, gun in hand. "Lead the way, spouse."
"I'm ready too," Yui announces.
Olaea scratches irritably at her hand. There are white blotches breaking out there. She tucks her hand into an armpit. Nobody notices. "We should bring... food," she says.