A mysterious man sent an invitation to the soldiers. Their objective was to retake Shiba Castle. This castle belonged to the Sheba clan and had fallen into the hands of the Chaos Army 20 years ago. The twelve assembled soldiers received a playing card along with the invitation, as if to liken them to the spade knights who served Shiba Castle. However, they were ambushed, and the survivors were "Seven" and "Eight," the robots with two brains; "Jack," the one with the strongest shield; "Queen," the beautiful assassin; and finally, Cobra, who was holding the "Ace." They were heading towards the port town of Gizara in order to rescue "King," who was their only key to succeeding in sneaking into Shiba Castle.