Parola chiave Japan Self Defense Forces

Nei pressi del monte Fuji si schianta un disco volante che sprigiona una strana radiazione verde con il potere di fare resuscitare i morti in zombi. Nella zona diverse persone vengono a contatto con il fenomeno, i primi sono una squadra di militari che vedono resuscitare un cadavere di una donna suicida, poco distante un gruppo yakuza deve vedersela con un uomo giustiziato da una pallottola in testa che non ha nessuna intenzione di crepare, in un piccolo albergo nella foresta un tizio tenta di occultare il corpo dell'amante appena deceduta ma ignora che di li a poco tornerà trasformata in famelica zombi.

Off-duty Japan Self-Defense Forces (JSDF) officer and otaku, Youji Itami, is on his way to attend a doujin convention in Ginza, Tokyo when a mysterious portal in the shape of a large gate suddenly appears. From this gate, supernatural creatures and warriors clad in medieval armor emerge, charging through the city, killing and destroying everything in their path. With swift actions, Youji saves as many lives as he can while the rest of the JSDF direct their efforts towards stopping the invasion. Three months after the attack, Youji has been tasked with leading a special recon team, as part of a JSDF task force, that will be sent to the world beyond the gate—now being referred to as the "Special Region." They must travel into this unknown world in order to learn more about what they are dealing with and attempt to befriend the locals in hopes of creating peaceful ties with the ruling empire.

The Japanese Self-Defence Force suddenly time-travels to 1600s Japan in the middle of the epic battle of Sekigahara. With the latest weapons at their side, they join the battle.