Rayet, codenamed Scuro, works as an assassin for the infamous group Scarlet. His sole job is to assassinate other assassins as part of the "clean up team". Sick of taking lives, Rayet attempts to leave Scarlet. With the help of a fortune teller named Junki and his assistant Ritsuna, Rayet may succeed. However, Scarlet's rules do not contain a way to let him leave alive.