"Alone" follows Aidan (Tyler Posey), who barricades himself inside his apartment when his complex is overrun by infected screamers. With the world falling into chaos, Aidan discovers a girl (Summer Spiro) across his courtyard who is also trapped inside her house and now must find a way out for both of them. Over the course of the movie, the distance between Spiro and Posey turns into a tantalizing love story between these two characters stuck all alone.