In 18th-century Taiwan, where countless mysterious spirits reside, a boy named Shanan carries a book with the power to seal demons. To break the "curse of immortality" placed upon him, he journeys from north to south with the demon cat, Yue. Shanan's tribe's guardian deity, the Northern God, inexplicably follows them everywhere, though it seems he isn't protecting Shanan. Wherever they go, strange phenomena always surround them.