A rescue mission where you save some cats or dogs from an infestation and when you get back to base they now inhabit your base with you (i.e. you see them walking around the base every once in a while).
A friendly enclave calls you on the radio and says they saw some cats (or dogs) living inside a local house but they are in trouble because a horde rolled in on them. Will you help?
You go to their base and say yes ill help (or I guess refuse like a jerk face). They follow you.
You arrive at the location and kill the infestation.
You then need to talk to the enclave following you and they convince you to take the animal home.
Once you arrive home the animal can be seen walking around camp all the time, strictly as visual eye candy. You community gets a permanent +3 Morale bump and the animal follows you if you move bases.