The plot of the movie is that the main character has been charged with the death of a suspect in the murder investigation over which he had responsibility. Technically, the suspect was killed in a traffic accident while trying to flee interrogation, but the blame falls on our poor hero, who is accused of ordering a brutal interrogation and forcing the suspect to attempt escape. Thus the whole movie revolves around whether he will be found guilty of this crime.
I bought this cell phone strap after the movie at the merchandise counter. In Japanese, "black" means guilty and "white" means innocent. So when it says "He's black?" it really means "Is he guilty?" <snicker> Oh, Japan, you slay me.
It just so happened that the movie theater was right next door to a bookstore, so of course I had to go shopping. I will no doubt spend the next while reading all my purchases.