A postcard of Calgary. There appears to be a message for Billy on the back from a woman named Loretta, whom he presumably was having an affair with.
(On reverse side)
North West Mines
I had a great time.
Look me up if you're ever in Calgary!
After Emily falls down from hiding, and possibly lights her flare, make your way to the very right. A small wooden hut-like place will bear the romantic postcard.