On a snowy night in Tokyo, a 7-year-old child fell on the street with an extremely sharp sword beside him.
"Grandma, let's save him, okay?"
"Who are you?" Asked a pretty little girl.
"I don't know, I don't remember anything!" The boy woke up lying on the hospital bed.
"Then you will be my brother from now on, you must protect me!"
Looking at the innocent and cute little girl in front of him, the boy nodded and made a solemn promise, "Okay"
This year, there are still ten years before the main line of Conan.