A small three-story house is put up for rent in the neighbourhood and the Detective Boys decide to pass by it on the way home from school. Haibara tricks the real estate agent into giving them a tour of the inside and Conan notices that he could see Mouri's detective agency from the third floor window. The next day, they discover the house has been sold to an old couple and Conan finds them suspicious. He follows the old man to Chinatown and into an antique shop. The old man is talking with an old Chinese man; Conan is discovered and flees from the scene. Later that day, Conan notices that the house has a camera directed towards the Mouri agency and deduces the old couples are people using a disguise. Conan takes a nap upon coming home and a man in black enters with a gun. The old woman rushes to the agency who Conan greets as his mother. The man in black is Agasa in disguise and was used to lure his mother there. Conan reveals that he became suspicious when his father, disguised as the old man, pushed himself up with his hand to stand; An old man would only do that during seclusion to give other people the sense of his health. Vivian reveals that she was curious about Conan's daily life and that she wanted more pictures of a young Shinichi.