Finding a BL

Can someone help me find a BL which I vaguely remember but forgot the title of?. Not even chatgpt found it. Anyways, it’s starts in a dystopian concept with two opposing forces. One day the MC looses his group on a mission (I think) and he gets lost. Then the ML finds him and brings him to their shelter. The MC being from the other force, now has to make up a fake identity so that he won’t get caught. I don’t remember much past that point. I do remember the MC trying to communicate with his shelter in secret and almost ends up getting caught by another guy. Can someone please help me find it