In the seventeenth century, Japan is divided between two forces. The Eastern Army, lead by the Warlord Tokugawa Ieyasu, and the Western Army, which fights for Toyotomi's clan. Despite wining a recent battle, things look grim for the Eastern Army. Toyotomi's Army has a supply of modern firearms, a weapon which might turn the tides of war. Tokugawa Ieyasu sends his trusted samurai Mayeda, and his son Yourimune, to Spain. There, they are to purchase five thousand muskets. But it's a dangerous journey, and there are many who plot against them, and when they finally arrive in Spain, nothing goes the way they expected.