as the story opens,what emotion overcame the man?

I don't really think any emotion came over him. I think that was his problem. He was not weary of the perils that awaited him. Check out this quote,

"But all this—the mysterious, far-reaching hair-line trail, the absence of sun from the sky, the tremendous cold, and the strangeness and weirdness of it all—made no impression on the man. It was not because he was long used to it. He was a newcomer in the land, a chechaquo, and this was his first winter. The trouble with him was that he was without imagination."