Description?

One sudden morning in Beacon Hills, California, a guy came to the Stilinski household with his body worn out and drench with sweat. He suddenly passed out, when a teenager opened the door. Without consent, the teenager dragged the guy inside his house and placed him on his couch. He then came to notice that the unconscious guy in front of him is the one he was looking for.

What will the pack do when they know a secret of the stilinski family?

Who is this guy that suddenly came to Beacon Hills?

UNEDITED