Short Outside

I recently discovered a loose landscape wire outside my front steps in our last snow. This is the first time I've heard any noise and it was a very clear low voltage sounding short, much like what I've heard before when doing landscape light. It's also low voltage wire type. There was no breaker blown and the full circuit worked. In the course of trying to determine what all was on this circuit, it finally threw the breaker and now that breaker won't turn on. It's a dual 15A breaker that controls some overhead lights in the basement and one outlet directly below the front steps in the basement. The wire appears to come outside somewhere in that area and the rest of the circuit makes sense that way too. Directly under the foyer is an overhead light, from that light is a clear path to the breaker box, right under the light is the lone outlet that doesn't work now, and then inwards to the house are wires for two switches at the top of the steps and entry from garage to the basement.

I believe I am looking for some form of junction box that takes a wire outside, but that would be behind drywall. I'm looking at the Klein ET450 to help trace things inside, but what else might I be looking for? Is it possible there's a low voltage transformer behind the wall for this circuit, or is there randomly a landscape wire that's 120v and it is only now an issue. No changes outside for over a year and a half, to include snow, rain, puddles, and so on.