Garet James and Will Hughes find themselves back in 21st century Paris, each with an unusual romantic quandary. The 400 year-old remorseful vampire that Garet still loves remains trapped in time, in 1602, as is Marguerite, the young Will's love, who might reconsider her decision to reject him now that he has become an unvampire.
Their time reversing prospects include guidance from the Institut Chronologique and from another time-traveller, the astronomer Johannes Kepler who Will encounters on one of the bridges across the Seine. It is by no means an easy task. And complicating things further is the fact that they appear to have brought with them a monster from the past: the shape-shifting, blood-drinking Marduk.
They set out to find Marduk, but it's not easy to find a creature who can change shape at will. When they realize that Marduk has not only stolen Will Hughes' face, but also his identity, they fear that he has teamed up with their old nemeses John Dee and Cosimo Ruggieri to gain control of - and destroy - the world's financial markets. And when they learn that Marduk is on his way to New York, Garet fears that her family and friends will be his next target. Will and Garet leave Paris for New York, where they also hope to resolve their own romantic dilemmas.
Which Will does Garet really love? The innocent young man - or the man wracked with remorse for his history of violence and bloodshed? And does Will still love Marguerite? Or has he fallen in love with her time-travelling descendant?