Kitty Katz's mind is as crowded as Piccadilly Circus, the constant hubbub of conversation in her brain a relentless background to her own thoughts. Lying in hospital with concussion, a voice reaches out to her, forcing out the steady clamour of noise as it connects with her mind. Dominic Peverell is a Guardian desperately seeking his soul twin to prevent his inevitable transformation into a demon. Dominic brings peace to Kitty's chaotic mind - but he also brings danger. Unbeknown to Kitty, only she can prevent Dominic's descent into darkness - and now evil forces have turned their attention towards her, intent on destroying her before she can save him. Secretly shadowing Kitty is Dominic's brother, Conan, a newly turned demon. Kitty stands between the brothers and Conan is determined to destroy her. However, Kitty is not as easily destroyed as he and his fellow demons assume...