Author Kim Harrison brings us a crossover tale for her two main characters, Rachel Morgan ( the hollows) & Peri Reed, (Peri Reed Chronicles) they two heroines meet by accident when Peri's partner Jack casts a summoning spell with out knowing that he did and that brings Rachel Morgan into Peri's universe. This is a fast story to get through and it's interesting to see how these two hero's learn to get along and work together. If you like parallel universe travel or just these two hero's then I highly recommend picking up a copy of this story.