Murky/uncharted waters phrase
A situation that is unfamiliar to someone and potentially dangerous or difficult.
As I walked inside that abandoned house, I realized that I was getting into completely murky waters.
When I first visited Vietnam, I was in uncharted waters crossing busy streets.
When he first started working as a Youtuber, he entered murky waters of copyright law.
The origin of this phrase is not clear.
A legal matter that is very easy to solve
The house owners didn't lock the doors before going out, and that's why they got broken in. This is an open and shut case.