Rayet, operating under the codename Scuro, serves as an assassin for the notorious organization Scarlet. His exclusive duty involves eliminating other assassins as a member of the "clean up team." Weary of taking lives, Rayet tries to defect from Scarlet. Assisted by a fortune teller named Juki and her assistant Ritsuna, he might just manage to escape. However, Scarlet has no intention of allowing him to leave alive.