Why is Pikachu talking and wearing a Sherlock hat? WHAT IS HAPPENING?

I really don't know what to make of this trailer for an upcoming mystery game starring Pikachu in a Sherlock Holmes hat. "Oh, Pokemon mystery game," I thought. "I'm sure that'll be cute!" And then Pikachu opens his mouth and starts talking , with a voice that sounds like an adult man, and then he starts poking at unconscious bodies lying in the street and stealing kisses in a dark alleyway. Stop looking