The story begins with Michio Tsuchida, a 35-year-old office worker, diligently processing invoices on a Saturday evening. Feeling overworked and underappreciated, he decides to treat himself to premium beer and a lie-in the next day. As he walks towards the station, he hears a woman's desperate screams. He witnesses a disturbing scene: a man with grotesque makeup, holding a young girl by the neck with one hand and a knife in the other, muttering about sacrificing her to a deity named Merigas to be transported to another world. Despite the onlookers' hesitation and the delay in police arrival, Michio, driven by a premonition of danger and a desire to protect the child, charges at the man.
The collision knocks both the girl and Michio down, separating her from the attacker. The man, however, quickly recovers and lunges at the girl again. Michio shields her, taking two knife wounds to his back and waist. The arrival of the police apprehends the attacker, and the girl's mother rushes to her side. As Michio's consciousness fades, he hears the mother's thanks and another voice whispering "Thank you."
He awakens to unfamiliar voices calling him "Kain" and urging him to wake up. He finds himself in a bed, attended by servants and a woman he instinctively calls "Mother." A sudden influx of information overwhelms him, revealing he is Kain von Sanrose, the 5-year-old fourth son of Viscount Luke von Sanrose. He also learns that his biological mother, Linol, died a year prior and that his father's first wife, Lydia, has been raising him like her own child. Kain, retaining Michio's memories, grieves for his mother and recalls receiving something from her before she died, though its nature remains unknown.
Over the next two weeks, Kain recovers, grappling with his new identity and the memories of his past life. He finds comfort in Lydia's maternal care, though he struggles to act like a typical child. His older sister, Alice, also dotes on him. His father, Luke, visits, expressing concern about Kain's recovery and the upcoming "Baptismal Ceremony" at age five, where individuals receive a divine skill that typically dictates their life's path.
During the ceremony, Kain is guided by Bishop Sistina. He is transported to a white space where he meets Goddess Gardia, who reveals herself as the Earth Mother Goddess Gaia from his previous world. She thanks him for saving her granddaughter, whose body was being used as a vessel by the attacker. Gardia explains that intervening directly would have caused world imbalances, and Kain's sacrifice protected both her granddaughter and the world. As a reward, she grants him three skills: Earth Magic, Infinite Magic Power, and Magic Circle Magic. However, the skills are randomly selected due to past issues with reincarnators choosing overpowered abilities. She also bestows her minor blessing upon him.
Upon returning to the church, Kain's skills are revealed: Earth Magic, Magic Circle Magic, and the inherited Healing Magic from his mother. Luke is disappointed by the lack of combat-oriented skills, as these typically determine a noble's future. Kain, however, reassures his father, expressing his determination to master his skills and learn the necessary "Magic Manipulation" skill to utilize them fully. He also discovers, through his status screen, that his "Infinite Magic Power" is temporarily suppressed and that Gardia's blessing enhances his Earth and Healing Magic, provides minor status ailment resistance, and grants him the ability to understand foreign languages.
The story concludes with Kain resolving to explore the possibilities of his new life and skills, determined to make the most of his second chance in this magical world. He also learns from his father about the societal importance of skills and the risks associated with sharing one's status information.
