When Mr. Nebbercracker found Constance outside a carnival, he accidently startled her and asked her if she wanted to be taken away from there. She got overjoyed and accepted. Nebbercracker shown her the land he bough for them, and she got excited, so Mr. Nebbercracker started construction on the house. One day, while building the house, it was Halloween, and 2 children were standing by a bush, throwing eggs and things at her. With anger, she turned around and took Nebbercracker's axe and started swinging it around in rage. Nebbercracker tried to get the axe back, and calm her down, but this made her lose her balance and she pulled a lever, and fell into the House's basement, buried in cement, making her spirit stay in the house.
Years after her death, Nebbercracker continued to finish the house, as Constance would have wanted that. On October 31st, every year, he had to make precautions to keep children away from the house, to protect them, but lots of them didn't take notice of the signs, as they kept throwing stones and objects at his house.
More to come, feel free to add/edit