I'm trying to replace one of two 3-way switches with an occupancy sensing/motion detecting switch. I was expecting to see a pretty normal 3-way wiring but when I opened it up, I was surprised by the wiring as shown below in the image.
Descriptively: The box on the left has 3 romex wires. Two of those are effectively nutted (sorry) to eachother, white-white, black-black and bare-bare. The third romex goes straight to the switch with the white going to common. On the other box there is only ONE romex cable and this attaches directly to that switch, again white to common.
The wiring diagram from the booklet tells me that I need to first determine which switch has the "hot wire". Unless there is something happening in a junction box somewhere, this whole circuit seems like it's running on magic! What should I do as a next step?