The Beauregard estate sat on a hill that overlooked the Mississippi River, and from the veranda you could see the river bend like a sleeping snake, silver in the moonlight, brown in the afternoon sun, invisible at night when the fog rolled in from the delta and swallowed everything within a hundred yards. Corinne Beauregard had lived on this hill her entire thirty-four years, and she knew every inch of it: the crack in the third step of the veranda that had been there since her grandmother's time, the magnolia tree in the front yard that bloomed in April with flowers the size of dinner plates, the observatory dome on the highest point of the property, rusted and half-collapsed, where her father had spent his final years staring at the stars.

She inherited the estate, the debt, and the telescope when he died in the autumn of 1919. The estate was dying - the cotton fields had been exhausted by generations of careless farming, the outbuildings were rotting, the roof leaked in seventeen places. The debt was larger than she could comprehend. The telescope was the only thing that still worked.

Her father, Uncle Beauregard, had been an amateur astronomer with a genius for the impossible. In his final months, he became obsessed with a phenomenon he called "the flattening wave." He had detected it using a combination of astronomical observation and what he called "intuitive physics" - his term, not a scientific one. The wave was moving through space at approximately 0.3 times the speed of light, originating from the direction of Sagittarius, and it was changing the fundamental properties of matter as it passed. Specifically, it was reducing the number of spatial dimensions in its path from three to two.

Corinne thought he was mad. Grief had broken him, and his mind had broken with it. She cataloged his notes, boxed his instruments, and prepared to sell the estate when a stranger arrived from New Orleans.

Sister Marie was not actually a sister - she was a nun from the Convent of the Sacred Heart, but she preferred the title because, as she said, "Sister implies blood, and blood is a poor substitute for choice." She was forty, with sharp eyes and a mind that moved faster than most men's, and she had come to offer Corinne two things: companionship and scientific collaboration.

"I've read your father's notes," Sister Marie said, sitting on the veranda with a cup of coffee that Corinne had brewed too strong. "He was mad. But he was mad in the right direction."

"You think the flattening wave is real?"

"I think that three independent astronomers - your father, Dr. Moreau at the Toulouse observatory, and Professor Chen at Peking University - have all detected the same phenomenon from different directions. That is not coincidence. That is evidence."

"Evidence of what?"

"Of the end of the world."

Corinne should have been afraid. She was not. The Beauregard family had been dying for generations - tuberculosis, yellow fever, madness, the slow erosion of wealth and purpose that had turned a once-great dynasty into a family living in a rotting house on a hill. She was not afraid of the end of the world because she had been living in the end of the world her entire life. The estate was a tomb, and she was its last inhabitant.

They began to document everything. Corinne used the telescope to track the wave's progress through the outer solar system. Sister Marie kept a journal of the philosophical and theological implications. Together, they created a record that was part scientific observation, part elegy, part act of defiance against oblivion.

The first sign that the wave was closer than expected came in March 1920. Corinne was observing Jupiter through the telescope when she noticed something impossible: the Great Red Spot was changing shape. It was flattening, compressing from a three-dimensional storm into a two-dimensional stain on the surface of the planet. She recorded the change over three weeks, watching as Jupiter's greatest feature became a flat ellipse, then a line, then a point, and then disappeared entirely.

Jupiter had been flattened. The three-dimensional gas giant had been compressed into a two-dimensional disk, visible from Earth as a vast, spiraling pattern of color and light. It was the most beautiful thing Corinne had ever seen. It was also the most terrifying.

She wrote about it in her journal: "Jupiter is gone. In its place is a painting - a vast, swirling disk of ochre and crimson and white, rotating slowly in the sky like a coin spinning on a table. It is beautiful beyond words. It is the beauty of a thing that knows it is dying and has decided to make itself memorable before it goes."

Sister Marie wrote: "We are witnessing the undoing of creation. God spoke space into existence - height, width, depth - and now space is being spoken back into nothingness. What kind of God allows this? What kind of universe permits the gradual erasure of the dimension that makes life possible?"

Corinne did not answer. She was too busy watching.

The wave reached the asteroid belt in June. Corinne documented the destruction of thousands of small bodies - asteroids that had orbited the sun for billions of years, reduced to flat disks of rock and metal that spun silently in the vacuum. The asteroid belt became a ring of coins, each one a two-dimensional representation of a three-dimensional world.

In August, Saturn went. The rings came first - vast arcs of ice and rock that flattened into perfect circles, visible from Earth as thin lines of light across the planet. Then the planet itself compressed, its atmosphere collapsing into a two-dimensional swirl of ammonia and hydrogen that looked, to Corinne's telescope, like a watercolor painting left in the rain.

By October, the wave had passed the orbit of Mars. Corinne calculated, using her father's equations and her own observations, that the wave would reach Earth in approximately eight months. She told no one. What would she say? "Good morning, Uncle Beauregard. By the way, the universe is about to flatten us all into a painting. Would you like some tea?"

She continued documenting. She wrote about the estate - the history of the Beauregard family, the cotton fields, the slaves who had worked them, the descendants who still lived in the quarter house behind the main building. She wrote about her mother, who had died giving birth to her. She wrote about her father, who had spent his final years trying to understand the incomprehensible. She wrote about Sister Marie, who had chosen to stay rather than return to the convent.

Sister Marie wrote too. Her journal became a meditation on faith and oblivion: "If God is love, and love requires existence, and existence requires three dimensions, then the flattening wave is the undoing of God's work. But if God is beyond dimension - if God exists in a space that has no height, no width, no depth - then perhaps the wave is not the undoing of creation but its completion. Perhaps the universe was always meant to become a painting. Perhaps we are the brushstrokes."

Corinne read these entries and did not respond. She was an astronomer, not a theologian. But she understood the beauty in Sister Marie's words, even if she could not accept the theology.

The wave reached the inner solar system in March 1921. Venus flattened first - a bright point of light that suddenly expanded into a flat disk, reflecting sunlight in a pattern that was visible even during the day. Then Mercury, small and quick, gone in an instant.

Corinne sat on the veranda and watched Venus flatten. She watched the second planet from the sun become a two-dimensional object, a perfect circle of light and cloud that hung in the sky like a coin held up to the sun. She felt nothing. Not fear. Not sadness. Just the cold, clean clarity of observation. She was an astronomer, after all. Her job was to watch, not to feel.

But she felt. She felt the weight of the estate around her - the peeling paint, the rotting floors, the magnolia tree that had bloomed every April for as long as she could remember. She felt Sister Marie's hand on her shoulder, warm and solid and real. She felt the Mississippi River flowing below, three-dimensional water moving through three-dimensional space toward a three-dimensional sea that would soon cease to exist.

In May, the wave reached the orbit of Earth. Corinne and Sister Marie packed a single bag between them: Corinne's telescope lens (the glass had been ground by her father's hands), Sister Marie's journal, a bottle of wine from the Beauregard cellar (vintage 1890, the year the estate was founded), and Corinne's father's astronomical notes, sealed in a tin box.

They did not know what they were packing for. There was nowhere to go. The wave moved at 0.3 times the speed of light. By the time it reached Earth, it would encompass the entire planet simultaneously. There would be no evacuation, no escape, no last-minute rescue. There would only be the end.

They sat on the veranda in June and watched the stars disappear. One by one, the stars that the wave had already passed went dark - not because they were destroyed, but because they were flattened. A two-dimensional star is a two-dimensional circle of light, and from the right angle, it is invisible. The night sky was being erased, star by star, until only the stars beyond the wave's path remained.

Sister Marie held Corinne's hand. "Do you believe in an afterlife?" she asked.

"I believe in the wave," Corinne said. "I believe that when the wave passes, everything that was three-dimensional becomes two-dimensional. Everything that was complex becomes simple. Everything that was alive becomes... preserved. In a sense, we will last forever. A painting does not decay. A painting does not die. It simply is."

"That is not an afterlife. That is a museum."

"Is there a difference?"

Sister Marie was silent for a long time. Then she said, "I think the difference is that a museum is visited by someone. An afterlife is experienced by someone. If we become a painting and no one looks at it, have we really survived?"

Corinne did not answer. She was watching the sky.

In July, the wave reached the Moon. Corinne watched it through the telescope as the lunar surface flattened, the craters becoming flat circles, the mountains becoming flat ridges, the entire satellite compressed into a two-dimensional disk that hung in the night sky like a coin pressed between the pages of a book.

She placed her father's notes in the tin box and sealed it. She wrote a single sentence on a piece of paper and placed it inside: "We were here. We saw. We documented. This was enough."

She put the paper in the box with the telescope lens, the journal, and the wine. She did not know who would find the box. She did not know if anyone would find it. But she knew that the act of sealing it was an act of hope - not hope for survival, but hope that the act of documentation itself had meaning, that the act of witnessing was itself a form of resistance against oblivion.

In August, the wave reached Earth.

Corinne sat on the veranda of the Beauregard estate and watched the Mississippi River flatten. She watched the water become a flat sheet, then a flat line, then a flat circle of reflection that hung in the air where the river had been. She watched the trees in the yard become flat drawings, their leaves two-dimensional shapes arranged on two-dimensional branches. She watched the sky compress, the clouds flattening into paintings of clouds, the blue of the atmosphere becoming a thin, flat layer between the earth and the void.

Sister Marie was beside her, holding her hand, crying silently. Corinne held her hand back. She was not crying. She was observing. This was what she had been trained to do - to watch the universe with clear, unblinking eyes, to record what she saw without flinching, to find beauty even in destruction.

The estate began to flatten. The veranda became a flat surface. The floor beneath her feet became a flat plane. The walls of the house became flat paintings of walls, the furniture inside becoming flat arrangements of color and shape. The magnolia tree in the yard became a flat circle of green and white, a painting of a tree that would never bloom again but would never cease to bloom.

Corinne looked up at the sky one final time. The sun was flattening - a circle becoming a line becoming a point becoming nothing. The stars beyond the wave's path still shone, three-dimensional points of light in a three-dimensional universe that was slowly consuming everything in its path.

She thought about her father, who had predicted this and spent his final years documenting it. She thought about Sister Marie, who had chosen to stay and face the end with dignity. She thought about the tin box, sealed and waiting, containing the record of their existence.

She thought about the river, now a flat sheet of reflection, and the sky, now a flat layer of blue, and the estate, now a flat painting of a house on a hill.

She thought about the universe, vast and three-dimensional and beautiful, and she thought about the wave, patient and inevitable and flat.

And she thought: we were here. We saw. We documented.

The veranda flattened beneath her. The air flattened around her. The world flattened into a single, perfect, eternal painting - the Beauregard estate on a hill overlooking a flat river, two women sitting on a flat veranda, watching a flat sky, and in the center of the painting, a tin box, sealed and waiting, containing the record of a civilization that had existed in three dimensions and had been compressed into two, not in death but in transformation, not in destruction but in preservation.

The painting would last forever.