Wiring problem

Hey guys,

I recently inherited an electric guitar but it does not work. All you can hear is noise (which volume can be altered with potentiometer, only one there). I unscrewed the lid and checked the wiring. It appears that I have a loose one as you can see here. Because it's black (duh) and it's soldered to a metal plate (duh duh) I assume it's ground. Where should the other end go? Here is the close-up of potentiometer.

PS I've checked the pot with a multimeter, seems like resistance values are ok, so I'd not blame it for noise problems