Weiß is a clandestine squad of four assassins haunted by their pasts: Omi Tsukiyono, Aya Fujimiya, Ken Hidaka, and Youji Kudo. Bearing the scars of their memories, they adroitly wipe out felons who have eluded the law or operate beyond its jurisdiction. Gradually, they unearth the connections of these crimes to a more ominous scheme that touches upon their own histories. However, as they grapple with their consciences, they must weigh the price of championing their convictions and the ones they cherish against the loss of their humanity.