Synopsis
Rémi Letam awakens in the custody of the Ziel Council, a powerful secret organization made up of the world's rich and powerful as well as OMSIF, the council's private military force. Under the effects of a truth serum, Rémi explains to an interrogater that he joined the ON Peacekeepers as a pretext to sneak into his war-torn homeland of Hadea to search for his parents. He then begins to recount the events leading up to his capture.
Some time ago, Rémi arrives in Hadea, which is not only in the midst of a civil war between its Palomist and Sabinian ethnic groups, but also is infested with hostile supernatural creatures called Hollow Walkers that emerge from timeloops that perpetually repeat moments of intense emotion and violence. Rémi manages to scavenge weaponry from a fallen OMSIF military squad capable of fighting the Hollow Walkers and commandeers an abandoned APC. In search of his parents, Rémi travels to his birthplace of Jova, which is now under military occupation and besieged by Hollow Walkers. Rémi discovers that his father is named Vitalis, and is part of an enigmatic organization called the Vigil that is aware of the existence of the Hollow Walkers, but has already left the village. Following his father's trail, Rémi finds Vitalis mortally wounded after a battle with OMSIF forces. Recognising Rémi as his son, Vitalis explains he and the Vigil are sworn to protect Hadea and put a stop to the Calamity giving rise to the Hollow Walkers. He passes an item called the Keystone of Grief on to Rémi and bids him to find the journalist Tania Alver. Before passing away, Vitalis claims that Rémi's mother is dead.
Rémi links up with Tania, and they continue to investigate the Vigil, discovering that the Keystone will unlock something referred to as the Failsafe, which can supposedly stop the Calamity. Eventually, they discover the door that the Keystone of Grief opens, but find they need three additional Keystones to open it. They also receive covert assistance from an OMSIF officer who allows them access to OMSIF's Ziel Server, which contains sensitive information about Hadea's history. Rémi follows the trail of the remaining keystones across Hadea, searching ruins and collapsing Timeloops along his journey.
As Rémi explores Hadea in search of the keystones, he discovers more about the secret history of Hadea, and about the Calamities that had previously occurred throughout the country's history. Rémi continues to be contacted by the OMSIF officer, who eventually reveals that she is Aribeth Letam, Rémi's mother who smuggled him out of Hadea. Before they can meet however, OMSIF discovers her betrayal and attempts to apprehend her, and she is seemingly killed in a struggle.
With all of the Keystones collected, Rémi unlocks the door leading to the Failsafe, which leads to a massive underground chamber containing the Eye of God, a large sphere believed to be the eye of the Hadean God Sethyris, the source of the Timeloops and subsequently the Hollow Walkers. OMSIF had already set up a lab to study the Eye, but the entire research team was wiped out by Hollow Walkers. Rémi fights his way through the Hollow Walkers and activates the Failsafe, which collapses the entire chamber and drops the Eye into a pool of lava below, semmingly destroying it. Rémi narrowly escapes the chamber but is captured by OMSIF forces.
Back in the present, the interrogator taunts Rémi that Aribeth betrayed the Vigil after being given falsified evidence that Vitalis informed the police about Rémi being smuggled out of Hadea. As the interrogator prepares to execute Rémi, Aribeth arrives and kills the interrogator, having faked her own death. She frees Rémi and escapes with him, telling him that they are going home.
In a post-credits scene, an OMSIF drone discovers that the Eye of God has survived the failsafe.
