Transferring human consciousness into a robotic "I-Machine" is now possible, thanks to the discovery of a valuable ore known as "orichalt." However, there remains a risk that the consciousness may not return to the original body, potentially leaving the individual permanently trapped within their new metallic form. This is the fate of members of the Excavate Company, a group of reckless I-Machine miners led by the infamous Grayman, who seek orichalt for profit. During a mining operation, the group rescues Maya Mikuri, a student who was left behind by her crew. Accused by her former colleagues of stealing classified information about orichalt, she joins the Excavate Company in an attempt to prove her innocence. Their journey then begins, one that will alter their lives—including that of Ido, a skilled member of the group who has no memory of his past. For the first time, Ido might have the opportunity to uncover his true identity.