What is the conflict of the book brians winter?

At the end of Brian's Winter, Brian had himself rescued thanks to the family of Cree trappers, the Smallhorns. Every month, a plane comes to the Canadian wilderness to give the Smallhorns the supply they need. In the end, Brian got on the plane. But, Mr.Smallhorn

( I think that's his name... ) knew how he felt. Brian has become attached to the wild. So, he said "Don't worry. We'll leave the soup hot when you come back." Okay, he said something like that. Brian just smiled and went up on the plane.

That's about it!