The Lie (1918)

Elinor Shale's happiness at being engaged to Gerald Forster is interrupted by the arrival of her sister Lucy, who confesses that she will soon give birth to an illegitimate child. Elinor goes into seclusion with her sister until the baby is born and then tries to find a foster mother. Seeking to estrange Gerald from Elinor so that she may marry him herself, Lucy convinces him that Elinor is the child's mother. After Lucy and Gerald's marriage, Elinor learns of her sister's perfidy and resolves to tell Gerald the truth, but at the sight of their happiness, she relents and returns home.