I coveted my wife's family background and killed my girlfriend at the time. Over the years of our marriage, I gradually came to truly love my wife.
But then my girlfriend's younger sister suddenly came looking for me. A similar death had occurred in a nearby city, and she planned to reopen the investigation into the old case.
In the meantime, my wife noticed my strange behavior. We tested each other, until I finally struck the fatal blow.
But in the end, it turned out that everything I had done was completely unnecessary. The case in that city had nothing to do with the one from back then, and my girlfriend's sister had a ridiculous original reason for wanting to reopen the investigation. Of course, she wasn't the ridiculous one. I was.
I killed my wife for a ridiculous reason.
This is the story this novel tells.