In Ohmi, where the sun never breaks through the dark clouds, there lies an occult shrine. It is said that a pair of twins, born from purgatory, resides there. A secret mission has led the young samurai Sakichi to this place. Allegedly, he will find the Skull Hozuki here, a powerful artifact. But what exactly is it? The twins know, but Sakichi has no idea what kind of devilish entanglement he has gotten himself into with them.