While the film is a remake of a Thai film by the same name, ALONE is the story of Sanjana (Bipasha Basu) who is forced to return to Kerala with her husband Kabir (Karan Singh Grover) after her mother meets with an accident. When Sanjana, the survivor between conjoined twins comes home after years, she is thrown face first into her old life which is both painful and haunting.
In fact Sanjana’s return not just brings back distant memories, but it seems as if it also brought back her twin sister Anjana’s (Bipasha Basu) spirit whose presence is felt only by her. Continuing the déjà vu scenario, Sanjana shares her plight with Kabir but he believes that it is merely love for her sister and the guilt of losing Anjana that is leading to these hallucinations. However, these delusions soon grow into spine tingling incidents bringing Sanjana at the verge of a breakdown. Kabir takes help from his psychiatrist friend Namit only to realize that it is rather beyond science. Is the existence of Anjana’s spirit real or it is just a figment of Sanjana’s fervent guilt loaded imagination, is what forms the rest of the story.