 At age 17, Carmen Salazar left her grandmother, her little sister, Lauren, and the home she was raised in to pursue a better life. Nearly eight years later, we encounter her first trip back to her childhood home in Texas. She is welcomed only by a somber, empty house left to her by her now deceased grandmother that slowly begins to fill her with misery. On her first night, she realizes she is not alone when an eerie, mysterious visitor knocks persistently at her door driving Carmen into a state of terror, madness and fear for her life but what is even more horrifying is her realization of The Knocker s true identity.