The year is 1926, and Shanghai hums to the tune of debauchery. A blood feud between two gangs runs the streets red, leaving the city in chaos.
Juliette Cai is the proud heir of the Scarlet Gang  a network of criminals far above the law. Roma Montagov is the prodigal son of her greatest rivals, the White Flowers, who have fought the Scarlets for generations. He is also Juliette's first love and first betrayal. When a deadly madness strikes gangsters on both sides, the people start to whisper. Of a contagion, and a monster in the shadows. And as the deaths stack up, Juliette and Roma must set their guns - and grudges - aside and work together.