Callum is deployed to the Empire under the guise of Callum Ardere, the newly legitimized bastard son of Count Ardere, a noble family facing political freeze-out by more powerful factions. Upon his arrival at the grand family mansion, he is instantly met with hostility from his new half-sister, Alice, who challenges him to a duel to protect her inheritance. Callum easily humors her during the fight, choosing to dodge her fiery onslaught with minimal effort rather than retaliating, which showcases his superior speed and physical augmentation. This display of restraint puzzles the Count and Countess, who are secretly trying to gauge his strength to see if he is a tool sent by the Emperor or a threat to their house. After the battle, Callum is forced to learn the dizzying social rules of high nobility under the strict tutelage of his stepmother, Claire, before departing for the Academy. The journey to the school is filled with tension as Alice warns him of the ruthless political landscape, urging him to keep a low profile and avoid duels with other ambitious noble students. However, Callum's hopes of a quiet school life are immediately dashed when he enters the registration building and is forced to accept a mysterious covenant with a creepy, emaciated figure who controls the ancient wards of the school. He is left to wonder if his cover is already compromised as he is guided to a dusty classroom to take a placement exam that he is completely unprepared for, setting the stage for a series of academic disasters. To make matters worse, his practical exam is proctored by a drunken instructor named Ferguson, who throws him into a sparring match against a mysterious, highly skilled student. Callum quickly realizes that his opponent is incredibly fast, forcing him to momentarily raise his physical limits to land a decisive blow that shatters the student's defensive shell and caves in his nose. In the aftermath of the brutal clash, Callum is horrified to learn that he has just assaulted the Crown Prince of the Empire, leaving him to scramble for a way to cover up his actions before a massive geopolitical crisis erupts.

Despite the initial panic of caving in the face of the future Emperor, the Crown Prince, Rolland, decides to keep the incident a secret in exchange for future rematches, though he remains highly intrigued by Callum's mysterious strength. Alice is utterly mortified when she hears rumors of a new student striking the prince, dragging Callum into a supply closet to demand an explanation before public outrage ruins their family name. To prevent further complications, Callum is forced to join the advanced magical combat class taught by the eccentric Ferguson, placing him in direct contact with the school's top elites, including the arrogant ducal heir Marcus Procellae and the stern commoner Benjamin. During their first official class, Callum is matched against Benjamin, whom he defeats not through elegant magic but by using him as a human drumstick, slamming him repeatedly into the ground after being disarmed of his spear. This unconventional victory earns him the respect of his classmates but also draws unwanted attention from the nosey photography club and the manipulative Petro Lucerna, who seeks to use Callum as a pawn against House Ardere. Desperate to find a safe haven from the relentless club recruiters during the school's purging week, Callum is guided by the quiet library assistant, Mia, through a secret passage to the culinary club. There, he strikes a deal with Benjamin to join the roster as an inactive member, granting him access to an industrial kitchen where he can indulge in his passion for baking while avoiding the chaotic school politics. However, his peaceful sanctuary is threatened when he is confronted by the arrogant third prince, Sebastian, who demands a duel to avenge his brother's honor, forcing Callum to deliver a swift physical lesson in humility by vanishing from sight and leaving the boy bewildered. This encounter makes Callum realize that the royal family is far more complicated and volatile than he originally anticipated, with each brother harboring their own personal agendas that could compromise his mission.

Driven by the need to secure his cover against the school's lethal defensive wards, Callum conducts a daring night-time infiltration of the ancient registration building. He bypasses the security measures only to confront the creepy, emaciated caretaker, who reveals himself to be an ancient, primordial Spirit that is literally bound to the Academy itself. A violent clash of raw magic erupts between them, nearly tearing the temple apart as Callum unleashes his massive reserves and void-based energy to match the Spirit's colossal power. Realizing that Callum is a nigh-unkillable anomaly rather than a threat to the school, the Spirit halts the battle and agrees to a fragile alliance, promising to monitor the campus for any signs of a grand demon summoning. This breakthrough allows Callum to focus his investigation on the suspicious activities of Petro Lucerna, whom he begins to tail through the bustling streets of the city during his weekend excursions. With the help of his gossiping classmate, Anne, Callum uncovers a warded underground tunnel connecting Petro's properties to an illegal brothel, providing the perfect blackmail material to force the corrupt noble to back off. He shares this discovery with Alice and Lily, who are thrilled by the prospect of using this leverage to ruin Petro and restore their family's declining political influence. However, their plans are abruptly shattered when Callum receives a coded letter from his grocer contact indicating that his handler, Olivia, has gone missing after her cover was compromised. The sudden disappearance of his sole lifeline forces Callum to abandon all thoughts of school regulations, prompting him to seek out the local Federation spy network to launch a desperate rescue mission in the heart of the imperial city. He coordinates with the nervous rookie agent Lennard and the experienced Cassey at their secret safe house, preparing to tear the city apart to find her. As they analyze the clues, Callum realizes that Petro's faction is far more desperate and dangerous than he originally estimated, willing to resort to kidnapping to protect their illicit operations. With the clock ticking and the threat of the Justiciars looming over the Academy, Callum must navigate a web of betrayal to locate his handler before she is subjected to brutal interrogation.

To locate his abducted handler, Callum orchestrates a daring plan to let himself be captured by Petro's thugs, willingly wearing suppression cuffs to be led directly to their secret underground hideout. He is thrown into a damp, stone-brick cell where he reunites with a battered but resolute Olivia, who utilizes a rhythmic heartbeat code to communicate that she is ready to strike. When Petro enters the cell to gloat about his grand ambitions of seizing the Ardere heirship, he is accompanied by a mysterious, shrouded assassin known on the Federation's most wanted list as the Whistling Death. The moment Olivia gives the green light, Callum effortlessly shatters his metal cuffs, utilizing his peerless physical augmentation to vanish and instantly rip out the assassin's spine in a single, brutal motion. Olivia quickly subdues the terrified Petro, and Callum unleashes a searing flame to incinerate the corrupt noble where he lies, leaving no trace of his existence behind. The local Federation cleanup crew, led by Captain Davis, quickly collapses the sewer walls to flood the hideout with raw sewage, creating a disgusting barrier that will frustrate any future investigations by the imperial Justiciars. Although Callum manages to return to the Academy with a perfect alibi crafted by partying with Lily, his peace is short-lived as the Justiciars arrive on campus to investigate Petro's sudden disappearance. To make matters worse, Callum discovers a highly dangerous network of modified demon cores being distributed among the student body, forcing him to continue his dangerous investigation while avoiding the suspicious gazes of his classmates. He is cornered by the older Justiciar Vincent Promitia and his partner Janice, who attempt to unnerve him with a series of probing questions about his relationship with the missing noble. Callum is forced to play the part of an ignorant, slow-witted commoner to deflect their suspicions, relying on Alice's political protection to shield him from their authority. However, his cover is pushed to the limit when a violent altercation between the Justiciars and the hot-tempered Ferguson results in the near-destruction of the combat training grounds, leaving Callum to pick up the pieces of his shattered routine. As he balances the threat of the law with his training sessions with Marcus and his investigations into the demon cores, Callum realizes that the grand summoning is drawing closer, and he must act swiftly before the entire city is consumed by the forces of the hells.