Reincarnated from a peaceful death in old age, the protagonist awakens as a newborn baby girl named Riria in a marquis household. Her mother Claire dies in childbirth, and her father the marquis immediately blames her for the loss, declaring that if she had not been born, Claire would not have died. He orders her to be kept alive with a wet nurse but otherwise refuses to see her. The servants follow his lead, leaving Riria in near-total neglect. Only the wet nurse Martha cares for her physically, and the elderly butler Sebas visits at night when no one else is watching. Sebas cradles her, calls her by her name, and tells her about her mother, her brother Luke, and the sadness that has gripped the household. Riria retains her full adult memories and resolves to raise herself since no one else will. She trains her baby body by moving limbs and crying deliberately, though her efforts are limited by infant sleepiness.Over the first few months, Riria learns that her father cannot bear to look at her because she resembles Claire. Her brother Luke, who adored their mother, stays at the academy to avoid the mansion. Riria’s neck grows steady, she starts rolling over, and she babbles to Martha and the room. Sebas continues his nightly visits, calling her Riria-sama and explaining the family’s grief: the first wife divorced the marquis, Claire was a beloved second wife, and Luke is deeply attached to her memory. Because the staff fear the marquis’s reaction, they avoid Riria. Riria smiles and responds to Sebas to show her resilience. She thinks that without Martha and Sebas, a normal baby would become unresponsive, but she supplements the lack of affection with her own inner strength.Around six months, Riria achieves rolling over and can sit upright with help. One day she is grinning at nothing when a boy with blond hair and purple eyes enters the room and stares. She recognizes him as her brother Luke, who turns and runs away. Soon Luke begins standing in her room, staring wordlessly. He eventually pokes her cheeks, first too hard and later more gently after practicing with Sebas. He picks her up, acknowledges her warmth and softness, and says she feels like their mother. Riria calls him Nii-ni, and he calls her Riria. They hug, but Sebas finds them and scolds Luke for improper handling. Luke starts spending his summer vacation in Riria’s room, bringing a small table and chair to study. A carpet is laid on the floor, and a maid named Hanna is assigned to watch her. Luke feeds her baby food, reads picture books, and grows extremely attached. Riria learns that a week in this world is ten days, and weekends are two days off. Luke says he will come back every weekend during the school term.At eight months, Riria can stand up and crawl. Her bed is lowered so she can get off by herself. Luke returns to the academy, but Hanna stays with her. One afternoon Riria wakes from a nap to find the room empty and the door ajar. She crawls out into the corridor, heading away from the dead end. She eventually reaches the top of the stairs and is stopped by her father, who grabs her by the back of her clothes. He asks what she is doing and mutters that she looks like Claire. Riria does not cooperate. Servants appear, and Hanna apologizes for leaving her. Riria pats her father’s legs as if to tell him not to scold Hanna, which Sebas interprets accurately. The marquis orders her returned to her room. The father remains cold, unable to accept the child who caused his wife’s death. Riria concludes that she will simply use the family’s wealth to educate herself and escape when the time comes. The story follows Riria’s earliest months, her gradual physical development, the complicated emotions of her family, and her determination to survive without depending on her father’s affection.
