Ai Haibara, born Shiho Miyano, entered the world within the shadowy ranks of the Black Organization, a clandestine syndicate where her parents, scientists Atsushi and Elena Miyano, spearheaded the covert "Silver Bullet" project until their fatal accident. Raised alongside her sister Akemi, Shiho was funneled into continuing her parents’ work while Akemi lived outside the organization’s scientific grip. After rigorous education abroad, Shiho returned to Japan, ascending swiftly as a teenage prodigy codenamed "Sherry." By 18, she engineered APTX 4869, a poison designed for stealth killings, but concealed its rare de-aging side effect observed in lab tests. The drug’s accidental use on Shinichi Kudo triggered his transformation into Conan Edogawa. Discovering clues hinting at his survival during a covert investigation, Shiho falsified his death record to shield him. Her defiance ignited after the Black Organization executed Akemi, resulting in her imprisonment and planned demise. Choosing suicide via APTX 4869, she instead regressed to childhood, fleeing through a garbage chute before collapsing near Shinichi’s residence. Rescued by Professor Agasa, her parents’ historical ties to him unraveled. Assuming the identity Ai Haibara, she enrolled at Teitan Elementary, joining Conan and the Detective Boys. Initial wariness between her and Conan thawed into alliance as he acknowledged her antidote research. Haibara’s guarded exterior, shaped by fears of endangering allies, softened into trust with Agasa, Ran Mouri, and the Detective Boys. Her intellect and maturity starkly juxtapose her youthful guise, often prompting reminders for Conan to safeguard his secret. Destroyed research data stalled her APTX 4869 antidote progress, though temporary antidotes involving baijiu emerged. Pursued relentlessly by Black Organization operatives Gin and Vermouth, Haibara staged her death via train explosion—a ruse Vermouth sees through. She withholds intel on the organization’s enigmatic leader, Renya Karasuma, deterring Conan’s impulsiveness. Sarcasm veils her compassion, evident in her care for animals and subtle support for friends. She admires soccer star Ryusuke Higo, resonating with his betrayal narrative, and indulges a covert passion for fashion, citing Prada handbags, Fusae wallets, and *ComCom* magazines during missions. Nostalgic cravings for peanut butter and blueberry jelly sandwiches from her U.S. years surface, though she resists them around Agasa. Haibara and Conan’s bond oscillates between collaboration and friction, marked by identity-swapping disguises and antidote-fueled alibis. While peers muse over romantic undertones, their alliance remains rooted in survival, with Haibara acknowledging Conan’s role in enduring their shrunken lives—a partnership balancing tension and mutual reliance.