It is eight years since Xuan Wu, God of the Northern Heavens, living in Hong Kong as wealthy businessman John Chen, was exiled from the mortal realm. Emma and Simone are facing a new series of threats. Leo, their best fighter, is sitting in Hell, but when they journey below to persuade him home, nothing is as it appears.

On Earth, Simon Wong, the Demon King's son, is no longer around to trouble them, but his associates have taken over Simon's underworld activities. The otherworldly stones are being targeted and are in danger of their kind being completely destroyed.

It seems that the Demon King is the only one Emma can turn to for help ...