Mabel Reed, raised in an orphanage and longing for family love, faces constant neglect and isolation at home due to her family's biases. Heidi, the Reeds' adopted daughter, secretly replaces Mabel’s medication with vitamins, worsening her stomach illness until it advances to gastric cancer. Her family, believing Heidi’s lies, accuses Mabel of faking her illness for sympathy. Eventually, Heidi's schemes lead to Mabel being cast out and brutally murdered.