Nat Bones is an OC (the mother of Hogwarts student Susan Bones, who is the niece of Amelia and Edgar). So far, all other characters are JKR's.
It was a beautiful day, the gulls chattering to each other, the sun glinting off the waves. She ran, laughing, far ahead of her sister and her brother, her long dark braid coming undone and flying around wildly as she careened down the hill. Her sister called to her, but her voice was faint now, carried away by the wind. Nat stopped and grinned with mischief as she saw the little boat floating next to a rickety dock by the lake's shore. She went down into the shifting shade, through the sticky, damp clay. She climbed into the boat. Lying down in the bottom of the boat, she hid, relishing the smell of the lake and the feeling of the warm water that splashed onto her hated pink pinafore. The boat rocked gently. She felt the sun hot on her hair. She waited.
It wasn't long before she heard her brother and sister tramping down the nearest hill, Amelia complaining all the way as though talking to herself. "…already four years old and she still doesn't listen. Not ever! And now mum's going to be cross. Ever since what happened with those Muggle girls… Natalie Jane Bones, where are you?" she called again. "Come back here!" Nat sprang up from the bottom of the boat, laughing, about to shout and startle her hapless siblings.
Nat registered the look of stricken horror in her sister's grey eyes before anything else. Then, her voice, sharp with urgency: "Edgar, run! Get Mum!" and the boy running, his eyes wide, as fast as his chubby little legs could carry him. Somehow, as Nat waited, the boat had floated away from the dock without her realizing. Amelia scrambled down the bank toward her sister, shouting something, nearly falling into the mud with her haste. She kept looking back and forth between her sister and the water as she approached. Her meticulously shined black shoes, her snowy white socks, even the hem of her usually spotless blue frock were splattered with mud. All of this was bad enough, wrong enough, but when Nat saw the tears sparkling on Amelia's cheeks, she was pierced by terror, profound and real. Her big sister never cried.
The boat began suddenly to pitch and heave sickeningly beneath her. She barely caught herself before falling out. Peering over the side of the boat, she realized with horror that dozens of tiny hands were pushing at it. Dozens of little faces stared up at her with an unreasoning, implacable malice. She was suddenly aware of how thin it was, how insubstantial, the hollow shell of wood and stretched canvas that kept her out of those grasping hands and those crushing depths. Her stomach twisted with dread.
Above the pounding waves and her sister's far-off shrieks she could hear, carried to her by the wind, her mother's voice, shouting. The boat shook and rocked again, and she crouched, frightened, willing it not to capsize.
As she watched, the sprites' faces seemed to contort simultaneously with fear. They vanished in all directions. She stared after them, her distress interrupted by confusion.
The lake went calm. The gulls fell silent. Nat looked down into the water. Something was wrong with the bottom of the lake. She had a horrible sense of vertigo, but she did not understand at first. When she did, her heart trembled, shuddered, and rolled, like the boat under her feet. Suddenly, somehow, something dark and monstrous and impossibly vast was rising beneath her, rising from the dizzying depths, rising toward her to swallow her whole.
She woke up, thrashing, tangled in the sheets. The hotel bed, the desk, the pictures on the wall were all quaking and rumbling with the force of her fear. The television tottered and crashed to the floor. Someone pounded on the door, hard, and she was up, crouching behind the door, wand in hand, her back to the wall. "What's going on in there?" The hotel manager. Just a Muggle. She tried to breathe. "Open up!"
She cracked the door, light streaming in and hurting her eyes. A jet of red light burst from her wand, and the Muggle flew backward, landing on the other side of the hallway in a heap. She closed the door and locked it again, then pulled on her clothes and boots, smoothing her long, graying hair into a knot. She picked up her little knapsack and left the hotel room. "Obliviate," she whispered, as she strode past the unconscious Muggle. Her nerves still crackling with fear, she walked out into the rain.
