> Bring the stranger cat an article of clothing from the floor of the first room. Maybe the scent will help. Also try and bring the bracelet.

When you get back upstairs again, the other cat has calmed down somewhat. By the time you've finished arranging the shirt and the bracelet in front of him, he's no longer growling at you.
But he doesn't seem interested in letting you get any closer, either.
Alison Wilgus 2013