The Dying of Souls

After Marlene von Bechstein's husband disappears without a trace, the wandering soul sets off in pursuit of his alleged kidnapper, Gregor Dubois. She is aided by former rocker Ares Löwenstein and funeral director and death-sleeper Konstantin Korff, who is also secretly dealing with problems of his own. However, their investigation in Leipzig, Vienna, and Quebec brings a few surprises.

And then there's the mysterious Inverno, who continues to hunt wandering souls to find out who robbed him of his memory.
Sia, an ancient vampire, is also on a quest. She intends to find out where her lover Eric and her ward Elena have disappeared to, and how the Libra organisation is connected to it all. However, her rescue mission doesn't go as planned: it leads Sia to unknown places from which there is almost no return. On top of all that, a fight awaits her with an enemy she did not expect.