The protagonist, a former programmer for a black company, found himself trapped in a repeating cycle. After enduring 30 years as a hero in another world, where he defeated the Demon King under the constant, nagging guidance of a "Sage's Soul" skill granted by a Goddess, he was returned to Earth. He reappeared moments before his original death by a dump truck, realizing this was a repeat of the event that first sent him to the other world. Refusing to relive the arduous hero's journey, he skillfully evaded the truck, choosing to break the cycle and embrace a mundane life free from the Sage's Soul's influence.
Back in his old job, his company faced bankruptcy due to a critical "Heisenbug" in their automotive AI, causing inexplicable accidents and a massive lawsuit. Despite his junior status, his "Appraisal Skill," honed in the other world, unexpectedly reactivated. This allowed him to intuitively understand the AI's complex code, quickly pinpointing the elusive bug in a section created by a legendary, departed programmer. When his incompetent Chief tried to steal credit and threatened him with company judo members, the protagonist, fed up with the treachery, used his combat-honed physical abilities (like adrenaline control) to easily neutralize the threats, punch his boss, and quit, feeling a profound sense of liberation.
Now jobless, the protagonist realized he needed to earn money. He decided to leverage his unique skills for "physical labor-based treasure hunting." He found an estate clean-up company, "Katakuzuke-dou," and negotiated a deal to buy interesting items found during clean-ups. His first job at a dusty mansion's storehouse proved highly successful; he used his Appraisal Skill to identify numerous genuine antiques, previously dismissed as fakes by the family, and sold them for a significant profit, validating his new career path.
During this period, he encountered Kasumi, a distraught young woman heartbroken after finding her boyfriend cheating. Despite his initial reluctance to get involved in a lovers' quarrel, his body's long-suppressed desires led him to agree to help her enact revenge. He orchestrated a dramatic makeover, transforming Kasumi into a sophisticated beauty, and then confronted the cheating boyfriend in a hotel room, implying intimacy. Using his negotiation skills and a touch of physical intimidation, he forced the boyfriend to apologize. However, Kasumi, seeing her ex's pathetic state, definitively broke up with him, feeling refreshed. The protagonist and Kasumi then became intimate, and she later moved into his apartment, having run away from her strict, academic family.
The protagonist's newfound success was further solidified when his former company's respected Integrated Chief sought him out. The bug he found was indeed critical, and the company desperately needed his help. He negotiated a high-paying, short-term contract, strategically planning to share his antique profits with the estate clean-up president to secure future treasure-hunting opportunities. From a man trapped in a predetermined loop, he had become a resourceful individual, using his extraordinary skills to navigate modern society on his own terms, with an unexpected companion by his side.
