I won't ruin it for you.
All you need to know upfront is this is a spec ad done by two German film students - Daniel Titz and Dorian Lebherz - for Johnnie Walker titled "Dear Brother."
The ad seems to follow two brothers on both a spiritual and physical journey to the most important places of their youth.
Once you get to the end, go back and watch again. I didn't see the ending coming, but once I did, I went back to put it together.
Then, go read this interview by AdWeek with the two filmmakers.