Whoever Slew Auntie Roo? (1972)

This is a retelling of the old tale of Hansel and Gretel, but set in England in the 1920s. To the children and staff at the orphanage, Auntie Roo is a kindly American widow who gives them a lavish Christmas party each year in her mansion, Forrest Grange. In reality, she is a severely disturbed woman, who keeps the mummified remains of her little daughter in a nursery in the attic. One Christmas, her eye falls upon a little girl who reminds her of her daughter and she imprisons her in her attic. Nobody believes her brother, Christopher, when he tells them what has happened, so he goes to rescue her.