Gabimaru, a ninja member of a clan of assassins, is sentenced to death. He claims to have nothing to tie him to life, yet no method of execution manages to end his life. His meeting with Sagiri Yamada Asaemon, who seems to be investigating him, will change everything.

The condemned criminals are gathered on the beach to prepare for the expedition to Shinsenkyo, but first, they must reduce their numbers.

Gabimaru, Sagiri, and the others arrive on Shinsenkyo, and their battle for survival begins.

Gabimaru and Sagiri's group cross paths with another Yamada Asaemon, Genji, who takes a dim view of Sagiri's involvement in the present matter. Meanwhile, Yamada Asaemon Tenza tries to find a way off the island along with his charge, Nurugai.

Mei attempts to explain something very important to Sagiri's party in the forest. Shion tries to explain how he interacts with the world to Nurugai. A mysterious servant of the Tensen tries to explain why Aza Chobe and Toma shouldn't escape.

Mu Dan confronts Sagiri's party and reveals shocking truths about the island's true nature.

Sagiri's party faces Mu Dan's seemingly unstoppable true form. Shion does his best to rise to the challenge with his mastery of waves.