As he took on more identities and each one grew increasingly prominent, Tangze became busier by the day. Except when it was explicitly for a commission, he no longer followed Mori Kogoro quite so closely.
First there had been Irish and the serial murder case bringing him work, then the work created by that family of masters, along with the Phantom Thief Troupe's daily affairs, Kisaragi Hōzui's exhibition, the new egg that was taking shape...
In short, while he had no time at all to spare for overlooked corners, Mori Kogoro's group had already met Rena Mizunashi.
Thinking it over, Tangze himself was still to blame. If he had not been so enthusiastic about teaching Mori Kogoro how to cook, Mori Kogoro might have declined a kitchen variety show where he could easily embarrass himself. But although Mori Kogoro's cooking had not yet become truly proficient, his cooking skill had improved considerably. The moment he heard it was a variety show involving cooking and casual conversation in a kitchen, with Yoko Okino as his partner, he accepted without a second thought.
And so, that inconspicuous commission quietly took place in some forgotten corner.
Every Saturday morning, Rena Mizunashi was subjected to a prank: she would hear the doorbell ring, open the door, and find no one there. With her overly sensitive identity, she immediately became wary and mentioned this troubling matter to Yoko Okino after running into her at the television station.
As the Great Detective Yoko Okino had always admired, Mori Kogoro was introduced to Rena Mizunashi and asked to solve this small, strange doorbell case for her.
The listening device Conan had attached outside the door as an aid for monitoring activity there was temporarily forgotten because they spent the entire night at Rena Mizunashi's house, observing and