Miguel did not think he would be returning to Mexico so soon, but when El Charro appears and asks for his help in finding out who is behind the darkness that appears to be spreading, Miguel agrees. La Llorona, searching for the same truth, enlists the help of Natalia, who wants to guarantee the safety of her brother and all children like him. As they travel their separate but similar paths, the legends they come across help them to understand that there may be other forces at play—some more powerful and ancient than they could have imagined.