For eons, the "Crimsons" have been under the tyranny of their hostile oppressors, the "Clients," who fancy themselves supreme beings. Even in the 1900s, the Crimsons still live in perpetual dread of the Clients, many of whom safeguard their lives by offering human sacrifices.
The Dark Hunter named Shion, who is a vampire and of mixed Crimson-Client heritage, along with his steadfast partner Rain, fights a ceaseless battle against the Clients. After encountering Helen, a young woman who has lost her kin to the Clients' savagery, Shion pledges loyalty and brings her into his fold. Helen becomes one of his devoted adherents by means of a blood oath.
