Shakugan no Shana follows the life of Yuuji Sakai, an average high school student living out his days as normal. One day, while returning home from school, everybody around him freezes and a battle breaks out between a mysterious stranger and two monsters known as Rinne. The stranger defeats this menace and returns everything to normal.
She introduces herself as a "Flame Haze" or someone whose job it is to defeat the Guze no Tomogora (beings that eat existences of humans) so as to maintain the balance of the world. Intrigued by what just took place, Yuuji follows this girl and asks her all kinds of questions as to what just happened. She explains to him that he is actually dead and simply exists now as a torch. Torches act as a filler from a person whose existence has been eaten by the Guze no Tomogora. Yuuji though is a special kind of Torch, known as a Mistes. The Mistes' hold within them certain powers that normal torches do not, and Yuuji's happens to be that unlike all other torches, he will not disappear. Now Shana decides to protect Yuuji because of his power and that all of the tomogora would be after him and his power.