Walker, a reincarnated adventurer, is exploring a dungeon with his party when a high-level monster attacks without warning. In that moment of desperate combat, his past life memories surge back with terrifying clarity. He realizes he has been living inside the world of a dark fantasy manga he once read, and his role is that of an ill-fated side character whose entire party is meant to be slaughtered to establish the story grim tone. Refusing to accept this fate, Walker fights with suicidal determination to save his companions. He succeeds in averting the total party wipe, but the victory costs him an eye and a leg, leaving his body permanently shattered.

As Walker struggles to adapt to a new life with severe injuries, believing his worst trials are behind him, the female members of his party begin to act in ways that are deeply unsettling. Their gratitude for being saved twists into something far more intense and unhealthy. One declares she will protect him this time no matter what and begs him not to abandon her, while another insists she will stay by his side forever, and a third announces she has decided to give her life for him. The cheerful and dependable comrades he once knew have become dangerously obsessive, their emotions warped by the trauma of their near-extinction and his sacrificial heroism. Walker saved their lives, but in doing so, he broke something inside each of them. Now trapped in a recovering body with a party that has become emotionally unhinged, this reincarnated man obsessed with securing a happy ending must navigate a new kind of nightmare where the greatest threat might not be monsters in a dungeon, but the intense and suffocating feelings of the allies he sacrificed everything to protect. The series follows his ongoing struggle to manage this twisted dynamic as more volumes continue to explore the fallout.