After a botched surgery leaves him with Empty Nose Syndrome, a desperate patient spirals into madness. When the black rain seeps into his mind, it transforms him into a terrifying agent of vengeance. In the same hospital, a young medical intern named Xiao Jian is caring for his comatose sister. As the infected patient slaughters the corrupt doctors one by one and unleashes chaos within the hospital, Xiao Jian tries to stop the bloodshed. But in the struggle, he is gravely injured, his blood mingles with the black rain... and something awakens inside him. Now granted a dark and dangerous power, Xiao Jian must decide: Will he protect what's left of his humanity, or become a monster to stop one?