When the brutal Boshin War breaks out in Japan, a group of inmates on death row unite to defend a fortress against the Imperial army.

Shun Fujishiro is a psychiatrist and works at a university hospital in Tokyo. He is engaged to Yayoi Sakamoto. One day in April, when he is about to marry Yayoi…

Taking place after the events of the TV series, Mitsuhashi and Ito face the new enemies.