The anniversary of the foundation of Shibusen is in full swing. All the students are gathered to celebrate the event with Master Shinigami in dignity. But in the shadows, the fearsome Medusa wants to take advantage of it to put her plan to execution and awaken Asura, the great devourer. Accompanied by Dr Stein, our young meisters go in pursuit of Medusa and his accomplices. A fight against the watch is engaged to prevent the return of this terrible demon.