Gaminaro is a ninja on death row who has one last chance to see his wife again by finding the elixir of immortality on a supernatural island and delivering it to the shogun. Faced with his executioners and the terrifying beasts roaming the island, he is determined to face every danger.

The palace has turned into a bloody battlefield, forcing the new arrivals Yamada Asaemon to form an unstable alliance with those seeking to escape the island. A giant monster has entered the battle, so enormous that everyone is trapped inside its body. If they don't escape by morning, they will transform into flowers and be used to trigger the destruction of everything they know!