CITY OF SOULS: Fourth Sign of the Zodiac - Vicki Pettersson

SO GOOD! I very rarely read a series book after book, but making a big ol' exception here. I love this series and I discovered after reading the third  one, THE TOUCH OF TWILIGHT, that I kind of needed to read the series back to back. I have them on the Nook and I want, no, I need to find out what is going to happen and I don't want to forget what's gone on before.
Joanna/Olivia (Jolivia as her team calls her) needs to find a cure for the little girl she inadvertently hurt. To do this, Joanna has to go to a parallel universe called Midheaven. The trip only costs a piece of her soul.
Action-packed and emotionally charged and highly recommendable.