Born Shiho Miyano into the Black Organization, Ai Haibara was the daughter of scientists Atsushi and Elena Miyano, who spearheaded the covert "Silver Bullet" project. After their accidental deaths, Shiho inherited their work. Educated in the United States from childhood, she returned to Japan and became an organization scientist by age 13 under the codename "Sherry." At approximately 18, she developed the lethal poison APTX 4869, designed for untraceable assassinations. During trials, she secretly observed a lab mouse regress to youth but withheld this anomaly. Following her sister Akemi Miyano’s murder by the organization, Shiho halted her research in defiance. Imprisoned and sentenced to execution, she ingested APTX 4869 to escape. The drug unexpectedly shrank her body to that of a 6- or 7-year-old. Fleeing to the residence of Shinichi Kudo—another victim—she collapsed outside and was discovered by Professor Agasa. Adopting the alias "Ai Haibara," she enrolled at Teitan Elementary School, joining the Detective Boys alongside Shinichi, now known as Conan Edogawa. Initially cold, cynical, and secretive to avoid endangering others, Haibara gradually bonded with Conan, Agasa, and the Detective Boys after revealing her identity and role in creating APTX 4869. Despite retaining a calm, sarcastic wit, she displayed kindness toward animals and self-sacrificing loyalty. Her personality included jealousy toward soccer idol Ryusuke Higo and singer Yoko Okino, and a fondness for peanut butter and blueberry jam sandwiches from her American years. Highly intelligent, Haibara contributed scientific expertise and knowledge in fields like theology and history to investigations. She pursued an APTX 4869 antidote, hindered by the organization’s destruction of research data. Discovering Baijiu temporarily reversed the drug’s effects accelerated her work. Though haunted by fear of Black Organization members Gin and Vermouth, she learned to trust Conan’s protective strategies. Key arcs defined her journey: In "Reunion with the Black Organization" (Episodes 176–178), captured by Pisco, she escaped by using alcohol to temporarily regain her adult form before being cornered by Gin and rescued. During the "Clash of Red and Black" (Episodes 492–504), she supported confrontations against the organization. In the "Mystery Train" arc (Episodes 701–704), targeted by Bourbon, Conan, Subaru Okiya, Yukiko Kudo, and Kaitou Kid staged her death in an explosion; Vermouth later confirmed her survival but concealed it. Haibara exhibited fashion savvy, requesting luxury items like Prada handbags or Fusae wallets in exchange for help. She read magazines such as "ComCom" and demonstrated makeup knowledge. As a Ryusuke Higo fan, she admired his resilience after betrayal, relating it to her own struggles. Her relationships were complex: She viewed Conan as a trusted ally, tempering his recklessness while depending on his protection. With Professor Agasa, she shared a familial bond, monitoring his health habits. She acted protectively toward the Detective Boys, especially comforting Ayumi Yoshida during crises. Unreciprocated romantic feelings for Conan contrasted with Mitsuhiko Tsuburaya’s crush on her. Haibara appeared in 392 anime episodes, 326 manga chapters, 18 movies, 12 OVAs, and 2 specials. Key episodes included her debut (Episode 129), where she rescued hostages and revealed her identity; Episode 140, aiding Ayumi’s rescue from an intruder; and Episode 345, where Vermouth initially spared her but broke the vow. In non-canon OVA 11, her fashion sense led to being mistaken for a child model. The 2023 compilation movie *The Story of Ai Haibara ~Black Iron Mystery Train~* recontextualized her arcs with new narration and animation corrections, including changing APTX 4869’s antidote color from red to blue.