While discussing Conan's journey to London and the case he had to solve there, Conan and Ai once again discuss Conan's reckless behavior in ingesting the anti-APTX 4869 meant for his return journey in order to reveal himself to Ran. An accidental comment makes the other Detective Boys suggest that they play hide and seek inside an abandoned building Genta knows.
As they begin playing (with Conan once again prevailing with his detective skills), Genta hears a strange knocking that Conan deduces is emergency code 252 - a plea for rescue. While searching through the building, they encounter two men, apparently demolition workers, who claim that they made the knocking sound with hammers. But noticing three consumed sushi bento boxes nearby and catching them with a trick question about how the house is to be torn down, Conan deduces they are fakes and have are really holding someone hostage in the building somewhere.
À peine rentré de ses aventures à Londres, Conan va jouer avec les Detective Boys dans un immeuble abandonné. Ils sont surpris par un appel de détresse et vont à la recherche de la personne. Cependant, ils tombent sur deux criminels, qui enlèvent Conan et Ai. Les Detective Boys vont devoir trouver un moyen de sauver leurs camarades!
I Detective Boys, Conan ed Ai decidono di giocare a nascondino all'interno di un edificio in costruzione. Genta, mentre cerca un nascondiglio, sente degli strani rumori e contatta gli amici per avvertirli dell'accaduto
Tras lo ocurrido en Londres, la liga juvenil de detectives de detectives va a un edificio que será derrumbado la próxima semana. Genta escucha golpes que hacen el número 252 que significa que alguien está secuestrado. Conan se da cuenta pero muy tarde y por eso él y Haibara son secuestrados mientras los demás intentan huir de ese edificio.
Després de l'ocorregut a Londres, la lliga juvenil de detectius de detectius va a un edifici que serà ensorrat la pròxima setmana. Gent escolta cops que fan el número 252 que significa que algú està segrestat. Conan se n'adona però molt tard i per això ell i Haibara són segrestats mentre els altres intenten fugir d'aquest edifici.
