"Tombs" are places where "relics" that grant supernatural abilities to their owners lie dormant. Ryoga Goriki, who made a living by robbing these tombs, is betrayed by his employer and teeters on the brink of death, only to be saved by a mysterious crow. He awakens in the world 15 years ago, when the tombs first appeared.
Having exposed a corrupt gallery's smuggling operation and secured funds, Ryoga was about to resume his grave robbing activities, using his knowledge and experience, when a tomb suddenly appeared where his home once stood. There, he found someone already attempting to infiltrate.
What appeared before Ryoga was a tomb where the artifact "Japanese sword Muramasa" rested. A malevolent aura permeated the interior, and many ordinary people were trapped inside. Ryoga finds himself in conflict with Rui, a member of the excavation team from the Republic of Bento, over "Muramasa"...