Catherine talks in a matter-of-fact way about the night her mother told her she was going to hang her.
"She brought a chair over and threw the rope across the beam. Myself and my brother were there that night. She said, wash your faces, I'm going to hang ye."
She turned her back to do something and the children ran away.
They returned later, of course. These children were used to the bizarre, and who, in any case, would have believed them?
This was Co Westmeath in the early 1970s in a rural area where terrible things were not supposed to happen. But for Catherine (not her real name), they had begun to happen a year earlier when she commenced five years of what she now describes as "imprisonment" at her mother's hands.
The previous September, when the other children in the family returned to school, Catherine, then 11 years old, was kept back by her mother.
She spent her days in a room in the house or in a shed beside the house. She was let out of the room to work in the kitchen, baking, washing clothes, ironing. When the work was done she went straight back to the room.
To this day, she does not know why her mother - who is still living - did this to her. No explanation was ever offered. To ask for one would have invited a beating.
"One time she locked us [Catherine and one of her brothers] in the house. She went out to the shed and got a can of paraffin oil. She brought it round to the back of the house.
"We could see her pouring this. She got a match and she just went to strike it. The back window was just made of a piece of wood with a bit of glass in it. We pulled that out and got out through that window and we ran for our lives."
When they returned she "murdered" them for running away.
Any fall-off in the standard of her work meant a beating with anything that was to hand, including a poker, an ashplant and a belt.
"Fear was always there with me."
The threats of hanging kept her in a state of fear. "She tried that on numerous occasions with me, tried to hang me. That was to terrorise me while I was there."
She always got away and still does not know whether these murder attempts were serious.
Catherine remembers her father with affection, but her mother hated him and frequently threatened to poison or stab him.
Her father, now dead, seems to have been a quiet, gentle man who never stood up to her. He seems to have stayed out of the house as much as he could, going to work and occupying himself at his own mother's house in the evenings.
After Catherine had been a year in the room, her brothers started to take turns to rape her. This happened when her mother had visitors, or was out of the house.
They were quick, brutal, silent rapes. It all happened in complete darkness. The kitchen was the only room in the house that had a light.
The rapes went on for four years. The first time she had a period she thought her brothers had "burst" her.
She is unable to get pregnant. She has had treatment for infertility but it has been unsuccessful. But for that, she might well have got pregnant during those four years.
If she had, "I wouldn't be here today, no way." She is certain her mother would have killed her or the baby to keep the family's business secret.
Catherine was not allowed a doctor if she was sick. Once, when she burned herself against a fire, her mother gave her a beating. She cried for days with pain. "The more I cried with the burn the more she would box me in the face to shut up."
Her mother told the primary school Catherine had gone to another school in the county. A Garda investigation in recent years found she was marked off the register of her local school in 1971, five years after she started school.
The register contains a note saying she had gone to another, named, school in the county, but that other school has no record of her ever having been there. The neighbours were told she was away at school in another county.
During the summer Catherine would reappear, apparently home from school. Her summer days were spent gathering up timber, cutting it with a manual saw, transporting it either by donkey and cart or by wheelbarrow back to the house, filling barrels of water with buckets from the river, transporting that, too, back to the house, washing clothes with an enamel bath and washboard, ironing, cooking, cleaning, cutting turf and the rest of it.
She remembers having a pet lamb which she fed on a bottle. When the lamb was sold the money was divided among her brothers.
"I wasn't able to relate myself to anybody," she says. "I couldn't confide in anybody and say this has happened. I had nobody."
Nor had she made friends at school. She did not start school until she was six years old - she does not know why - and this would have meant a big age difference between her and the other children in her class.
Her mother did not let her go to Confession in the local church when she was "home" for the summer, and instructed her always to stay at the back of the church for Mass. Her mother herself never went to Mass, a further factor of isolation for the family.
September brought a return to the dark room in the house. If anybody was likely to be in the house during the day, her mother would lock her in a cow shed. She would be there for the day.
Her mother would pass a mug of tea to her through an opening, and that might be all she would get for the day. She warned Catherine that if she moved or made noise she would chain her to the cow's manger.
She had to use the straw in the shed for a toilet (in the room she had a bucket and sometimes her brothers were there when she was using it).
The room she was kept in was her brothers' room. At night she slept in her mother's room. "I used to be afraid to sleep in case she would get up and choke me," she says. "I used to cry with fear as I could not see her move around in the dark. I always feared the danger of her hands around my throat.
"When she heard me crying under the clothes she would say, `Shut up or I'll murder you.'
"I thought one time about going to run away. And then I thought if I run away, I'll still have to come back, the police will bring me back, I used to think that, and I will be murdered."
When she was 17 the pretence that she was at school could no longer be kept up. She was let out of the room. She got a job. The first thing she did was buy a bra. It was the first she had ever had. Her father left the family home and she went to live with him nearby, in his house. One day she told the family she intended to expose what they had done to her.
"I said I'd open up the whole story. They said if you ever do, we'll get you. It doesn't matter how long it goes, we'll get you."
She has suffered a great deal from headaches, depression and pains. On one occasion she tried to take her own life.
In the 1990s she made a complaint to the Garda. Along the way towards making up her mind to tell the Garda, she rang Childline. "I rang them about three times and I felt great afterwards."
The Garda investigation went on for more than two years and confirmed that she had disappeared from the school system.
This summer, the Garda told her the DPP had decided not to prosecute the family because of the passage of time involved. She feels aggrieved by this. She produces a well-thumbed copy of Alan Shatter's book, Family Law in Ireland, and points to a paragraph about the rights of children. How is it, she asks, that children can have rights in textbooks but not in real life?
The Irish Times wrote to Catherine's mother and brothers inviting them to comment on her allegations, but they did not take up the offer