Wrong Money Letter

Father is dead. There was a circular burn on the body, which was charred black and had no smell of smoke, as if something had burned it through the clothes. The medical records had been altered, and all the documents on the table had been rummaged through, except for a letter box. Twelve hidden grooves correspond to twelve parts, each of which is hidden in an "ancient building that should not exist" - those buildings have never appeared on any maps, archives, or history books, but they really stand in a corner, waiting for people to find them. There were two people accompanying me: Lao Wu, who knew a lot; Ah Heng, who had a photographic memory. She said: "What my mentor saw back then was completely different from what was written in the records." After speaking, she stopped talking. Every time a piece of mail is put into the box, the crack in the base becomes an inch deeper. On the last page of my father's notebook, there is a line of words that has been scrawled repeatedly: "When the twelve are complete, the hall will open by itself." I have never heard of "". Ah Heng said that this word also appeared in her mentor's research notes—that notebook disappeared after her mentor's death. I've found five. The crack reached the center of the bottom of the box. Lao Wu finally spoke last night and said only six words: "Your father died by himself." Who left that burn? Who changed the medical records? What did Ah Heng's mentor see? If history can be tampered with - then is what I find the truth, or is it something others want me to see?