Casey (Odette Yustman), a beautiful girl in her prime, has been troubled recently. She often sees a boy with a gloomy face like a ghost looking at her with hatred. Casey seeks help from friends and doctors, but to no avail. However, she learns from an ophthalmologist that she may have twin brothers/sisters. This is later confirmed by her father. Casey finds clues by checking her mother's belongings and visits Sophie (Jane Alexander) in a nursing home, a survivor of the Holocaust during World War II. Sophie tells her about the cruel experiments that the Nazis conducted on twins in concentration camps. All of this is inextricably linked to Casey's experience. As the investigation deepens, Casey gets closer and closer to the truth...