After the tragic death of their mother when they were children, twin sisters Agata and Catalina Hameran developed a special skill, a way of communicating without speaking, a “link” between them. After a mysterious accident on Kilometer 31, Agata falls into a coma. Catalina, thanks to their “link”, feels the pain and tragedy that her sister is going through at the time of the accident. Following a series of supernatural events, Catalina realizes that their “link” is stronger than ever and that her sister Agata is screaming for help from her unconscious state.
Catalina is now determined to find out what really happened to her sister in order to help her wake up. Nuño, Agata’s long time friend, and Omar, Catalina’s boyfriend, agree to help her. But they soon find out that not only is Agata in a coma, but she is also trapped between reality and an ancient legend, the legend of La Llorona.