It's a magical world where magic is commonplace, and young Thomas Ward (Ben Barnes) is the seventh son of his father. He was born with the strange ability to see what is about to happen in the future while in a coma. One day, he is approached by a mysterious man, the famous demon hunter Gregory (Jeff Bridges). Over the years, Gregory has lost many of his disciples, so he seeks out Thomas, who is his seventh son, to take him on a path of cultivation like never before. Meanwhile, Malkin (Julianne Moore), the Queen of Darkness, is patiently waiting for the Night of the Blood Moon. Her powers will be greatly enhanced by that time, and her nemesis Gregory will never stand idly by.
　　With time ticking away, Thomas must become stronger as soon as possible...