20 year old Baekhyun's life changes when he witness his mother getting shot.

He then ater develops Posttraumatic stress disorder . He gets nervious very easily so to avoid that from happening, He is very cold to everyone other than his father and closest cousin, Kyungsoo.

The rich son of a well known business man, Byun Baekhyun is in danger when the killer finds out he is the one and only witness.

Park Chanyeol, a high ranking officer from the Witness Protection Unit is hired to protect Baekhyun from potential killers after the witness. 

What would happen between the two of them? And in the danger of his job, even if he manages to rescue Baekhyun countless times, will Chanyeol be able to protect his own life?