Detour

A man driving on an isolated road stops quickly when he sees a youth with a backpack on the side of the road. The driver glances at a photograph, puts it away, and offers a ride north; the youth accepts. They make small talk, they stop for tea. The driver says he's on his way to visit his daughter whom he hasn't seen in a year; he has flowers on the back seat. The youth says he has no family or friends - he confesses that when he looks at someone, he can see how and when they'll die. The film occasionally jumps ahead to events later that day. What's going on?