While the show still hasn't revealed many of its mysteries, the central conceit involves remotely exploring the minds of serial killers, via some fancy technology (the Wakamusubi) named after Japanese mythology. What's more interesting however, is the backstory of our "Brilliant Detective", Sakaido.
He seems to have committed some unspeakable crimes resulting in his current predicament as a prisoner in a prison for serial killers. The story beats are timed just right, with gradual reveals showing us what our "hero" has lost, as well as what he has currently become.
And he has lost much indeed, attempting to fill the holes in his heart with a certain dead artifact found in every serial killer's mindscape that he encounters.
Ultimately, what has me wanting more, however, is the very nature and insanity of this world our protagonist dwells in. A Japan plagued by an epidemic of serial killers, and that epidemic's root cause.
The initial episode features some brilliantly stylized animation and character designs, especially for the serial killer featured in that episode. While that upfront quality does dip slightly by the third episode, it's still very watchable and better than a lot of the generic isekai out there. As with most mystery shows, the show's quality hinges on the unraveling and resolution of the central mysteries surrounding the plot. I am firmly not in the camp that a mediocre ending completely undermines an otherwise good show...in most cases. But for a mystery show, there is a large element of delayed payoff, essentially an IOU issued by the show's creators that all the smoke and mirrors are worth it.
So far, it's looking like it will be.
