Use the Frosthound Collar at the Abandoned Camp to track down whoever took Brann's possessions. When you recover them, use the communication device and speak to whoever you can contact.
The tone of Brann's note suggests he meant to bury something with the note, maybe a pack of some kind. You're sure this was all you found?
Okay, I'm going to have you take one of these frosthounds with you. The frostborn use them for tracking. Bring it to the destroyed camp and let it get Brann's scent.
It should at least lead you to the location of those missing possessions, and if we're lucky, Brann himself.
Also, you get: 7 40
Who are you?
You... you're not a member of the Explorers' League, at least not one I remember. But, if you recovered the communicator, they must've sent you. Good, that's almost what I was hoping for.
Upon completion of this quest you will gain: