Poison (2001)

The darkly insidious story of the Garrett household and their descent into a hellish world of sexual malice and physical terror. Seeking revenge for her husband's death, Ann ingratiates herself with the Garretts under the guise of a caring housekeeper. Once she gains their trust, Ann begins to wreak havoc upon them. Seduction and malice are her weapons as she attempts to eliminate everyone she believes is responsible.