Gabimaru is a ninja on death row with one chance to see his wife again--by finding the elixir of immortality on a supernatural island and delivering it to the shogun. Standing in his way are his fellow convicts and the fearsome beasts that roam the island, devouring or killing anyone they encounter.

The palace has transformed into a bloody battleground, forcing the new Yamada Asaemon arrivals into an uneasy alliance with those seeking to escape the island. A giant monster has entered the fray, one so large that everyone is trapped within the confines of its body. If they don't escape by morning, they'll be transformed into flowers and used to fuel the destruction of everything they know!