Cordelia Beaumont returned to Oakhaven twenty years late and found the Beaumont plantation reduced to a skeleton picked clean by termites and vine. The house stood at the edge of the delta like a rotten tooth in a dying mouth, its wooden columns sagging, its windows hollow eyes. She had left at eighteen with a suitcase full of college books and a promise not to come back. Now she was thirty-four, unmarried, and returning because her grandmother Louise had died and the lawyer said someone had to sign papers.

The funeral was small. The Beaumonts had never been popular in Oakhaven. They were the sort of people who kept their doors locked at dusk and whose children played in silence.

Miss Cora Lee met her at the door with a kerosene lamp in one hand and a look in the other that Cordelia would remember for the rest of her life. At seventy, Miss Cora was the ghost of the household staff, the last living person who remembered when the Beaumonts were still people people spoke to in the street.

There is something in the cellar you need to see, Miss Cora said. But not tonight. The moon is too bright tonight. It will see you.

Cordelia went down alone while Miss Cora dozed in the par chair. The cellar stairs groaned under her feet. The air below was not musty. It was metallic, the way the taste of blood tastes when you bite down too hard on your sandwich. And there, in the centre of a floor stained with a century of delta damp, sat the thing: a perfect geometric solid, six feet high, black as polished obsidian, smooth enough that the lamplight did not reflect off it so much as sink into it. It was not a tetrahedron. It was a cube, or close to one, with edges so sharp they seemed to cut the air around them.

She began to research. The family records in the attic told a pattern every generation produced a different child. Great-grandmother Hester vanished into the delta marshes in 1870. Her son Tommy died of influenza in 1918, but the local undertaker's note, which Cordelia found folded inside a bible, said the body looked wrong: the fingers were bent at impossible angles, as though the hands had been digging at something right up until the moment of death.

Cordelia herself was the different child. Since she was seven, she had the same dream: standing before a black geometric object, watching it rotate--not physically, but in some dimension she could not name. Every morning, her fingertips were caked with dirt.

The Sputnik launch in October 1957 had shattered something in Oakhaven. Reverend Isaiah Beaumont, Cordelia's uncle, preached a sermon where he could not finish a sentence without repeating the word satellite four times. Dr. Raymond Whitfield, the only white doctor in town, had started drinking at breakfast. But Cordelia felt the thing in the cellar calling to her more strongly now, as though the satellite's launch had been some kind of signal, some kind of key turning in a lock she had not known existed.

On the seventh night, she took a shovel and a kerosene lamp and went back to the cellar. She dug around the base of the object. The earth gave way easily, as though it had been prepared for this. Her shovel struck something hard. Not stone. Bone.

She brushed away the dirt with her hands and found a human skeleton--or mostly human. The pelvis was too narrow. The skull was too elongated. And buried with the bones, wrapped in oilcloth, was a journal written in Louise Beaumont's hand: If you are reading this, the rotating chain has not ended. The thing in my cellar is not a stone. It is a seed. And it has been waiting for someone different enough to plant it.

Cordelia sat in the cellar with bone dust on her hands and Louise's journal open on her knees. She thought about driving away. She thought about getting back in her car and driving to Jackson and then to Memphis and then to Chicago, where she would change her name and become someone who did not come from places like Oakhaven.

Instead, she opened the journal to the first blank page and wrote: Day one of the new chain. The object is real. The bones are real. I am real, and I am different, and I am going to keep digging.

The moon outside the cellar window was full and yellow and watched everything the way the moon has always watched everything.