From the publisher:

Sohaku's lost his head--literally. But everything has gone according to plan. A look back at the past may shed some light on our heroes' fates. In a time of war, Sohaku schemes to have the Red Feathers take control of Osaka Castle. After witnessing the deaths of his friends and having to sacrifice his comrades, what does Ichiyo Nagi see before him now? Turning to face the final battle, the courses of the two eras flow into one, with all the pieces falling into place at the Todo Academy Preliminaries!