To many, only one possibility exists in this world—the one they believe in, and with that belief, agony inevitably follows.
Because they try to fit all the impossibilities into their perceived possibilities, without attempting to change or accommodate them.
Shen Yue was not such a person; he had a clear understanding of the case at hand that seemed simple yet was in fact complex.
Someone aimed to frame Inokawa Yukikazu, and they crafted a clever trap. They manipulated Flathead to humiliate Sachiko while altering the memories of both Flathead and Sachiko!
As a result, Sachiko believed it was Inokawa Yukikazu who had shamed her, while Flathead, his own memories of humiliating Sachiko erased, acted as if nothing had happened.
The criminal himself, with no recollection of his own misdeeds, becomes indistinguishable from a passerby; even the most experienced investigators can't discern any telltale signs.
This was the most ingenious aspect of the plot.