Flowers in the Attic — V.C. Andrews

Way upstairs there are four secrets hidden.
Blond, beautiful, innocent little secrets, struggling to stay alive.

The four Dollanganger children had such perfect lives -- a beautiful mother, a doting father, a lovely home. Then Daddy was killed in a car accident, and Momma could no longer support the family. So she began writing letters to her parents, her millionaire parents, whom the children had never heard of before.

Momma tells the children all about their rich grandparents, and how Chris and Cathy and the twins will live like princes and princesses in their grandparents' fancy mansion. The children are only too delighted by the prospect. But there are a few things that Momma hasn't told them.

She hasn't told them that their grandmother considers them "devil's spawn" who should never have been born. She hasn't told them that she has to hide them from their grandfather if she wants to inherit his fortune. She hasn't told them that they are to be locked away in an abandoned wing of the house with only the dark, airless attic to play in. But, Momma promises, it's only for a few days....

Then the days stretch into months, and the months into years. Desperately isolated, terrified of their grandmother, and increasingly convinced that their mother no longer cares about them, Chris and Cathy become all things to the twins and to each other. They cling to their love as their only hope, their only strength -- a love that is almost stronger than death.