Top-grade hitman Kim Jongin documents his toughest mission yet: to take out one of the most elusive assassins he has ever known, that just so happens to also be his ex-girlfriend, Roh Sunjung.

Howie finds a clue that could lead him to recover his lost memories in the form of a sequence of letters and a number: PZCY9. His chance at decoding this falls into his willingness to trust his coworkers at The Roundtable, who seem to be hiding secrets of their own.