No hot wire in switch box

I moved recently into a new house and had to replace an outdoor light and switch because both were dead. In the picture, the switch on the right is a 3-way switch that is wired and working fine. The left switch goes to the outdoor GFI switch and light. I replaced the GFI and wired it correctly but I’m still getting nothing. Everything works when I tie into the 3-way hot wire (but then the other 3-way switch has to stay on). Is there something I might be missing? Or do you think maybe the hot wire was cut somewhere? All the circuits from the breaker are good.