Technology advances to a point where it allows you to see yourself in parallel universes.  When Chanyeol decides to take a look for himself, he realizes he's dead in every other known universe. And the person who took out all his other versions has their sights on his universe next.

Memories lead us through our lives, gives us advice, sometimes good, sometimes bad. What will you remember of me, when I am not here anymore?

Sometimes it's important to get lost so you could find something. Be it a new coffee shop or a back-alley with a surprise at the end of it.