During a phone call with Ran, Conan pretends to be Shinichi, but his sneezes interrupt the conversation. When Ran asks him to come home, he excuses his absence with being on a tough case. Before he can say any more, Ran hangs up to answer the front door. Conan mentally grumbles about Ran's worried behavior as he walks home. He arrives to find a teenager in a baseball cap demanding that Ran stop hiding Shinichi. Conan sneezes, attracting Ran's attention, and she comments that Shinichi is also sick. The teenager asks how she knows, and Ran explains Shinichi's phone calls. The teen concludes that Sonoko's was right about them being together, to Ran and Conan's embarrassment, and asks if Shinichi ever asks how Ran is doing rather than talking solely about himself—to care enough to call but not ask after her, Shinichi is probably watching Ran from close by. As Conan wonders in shock who the teenager is, the teen takes off his cap and introduces himself as Heiji Hattori, another high school detective.
Conan sneezes again, unimpressed. Heiji explains that although Shinichi stopped appearing in the papers, people still compare Heiji to Shinichi, and Heiji wants to know if Shinichi is really a comparable detective. He also gives Conan a "cold cure", which turns out to be alcohol that he presents to Kogoro as a visiting gift. Another knock interrupts them, as a client, Kimie arrives with a request that Kogoro investigate her step-son's girlfriend, Yukiko. Kogoro comments that Yukiko appears perfect, and Heiji concludes that Kimie is suspicious about the perfection. Kimie wishes to have Kogoro also consult with her husband, Isao, in a low profile meeting at their home because Isao is a diplomat; Heiji convinces them to bring him, Ran and Conan along. Conan agrees in order to keep an eye on Heiji and what he might say, despite the alcohol having worsened his symptoms, while Heiji hopes that Shinichi might show up if Ran is along on the case.
At the house, Kimie introduces Kogoro as an old friend to the butler, Fumio. Before they get further, Yukiko arrives at the house and greets Kimie as "mother". Her presence shocks Kimie, and she angrily forbids Yukiko from calling her mother even though her step-son, Takayoshi, invited Yukiko over in order to meet Isao. The group also meets Isao's father, Toshimitsu, on the way to Isao's study. Toshimitsu, Takayoshi, Yukiko, and Fumio realize that Kogoro is actually a detective, and wonder why he would be there. At the study, Isao doesn't answer Kimie's knock, and she unlocks the door to reveal him sleeping sitting up at his desk, head propped on his arm. Heiji notes the opera playing while Kimie shakes Isao and tells him to wake up, only for Isao to fall to the floor, dead.
File 093 - Double Reasoning
File 094 - The Great Detective Of The East...!?
File 095 - The Great Detective Of The East Appears!?
