Family First is the mantra that has been drilled into Callie Delgado's head from birth. That's why when her brother, again, needs her help, Callie is there for him. This time, however, there's going to be more to her help than dishing out money. Callie's brother is in trouble with the mob and in order for Callie to keep her brother alive, she's asked to perform a dangerous, illegal task for them. 
 To do this, she'll need to rent a soul. Soul rental in quite popular in Gem City. If you want to commit a sin or a crime, you can rent someone else's soul, then the act is not tainted upon your soul. When the time comes to enter the afterlife, you'll have no marks against you. At least, that's what everyone is assured anyway. 
 Callie doesn't exactly have the money to rent a soul, but the Soul Charmer is willing to barter her work services in exchange for the use of a soul for a day. Not really being in a position to pass up the offer, Callie agrees and is then ensconced within the magical side of Gem City where she'll have to worry about losing her own soul in the process. 
 Borrowed Souls has a very interesting premise and the idea of renting souls to keep your own soul from being tainted is very clever, yet this first book is only an introduction to the gritty world of Gem City. 
 While I like the path that Borrowed Souls took in introducing us to this world, I honestly can't wait to see where else we'll be taken, along with Callie, as she learns the ins and outs of the soul charmer. 
 Callie was such a great character. The majority of events in Borrowed Souls stems from her dedication to her family which can be viewed as a strength but is also her biggest weakness as they honestly don't care much for Callie's well being. Yet she keeps, time and again, coming to their rescue. You want her to see what they're doing (and she does to some extent) and cut ties, but her loyalty to them speaks volumes about her character even if it's not for the best. 
 When you add the brooding Derek to the mix, who is helping Callie while she's indentured to the Soul Charmer, you witness him seeing her as more than the bail out. He sees Callie's loyalty and he doesn't demand anything in return. It's a good thing for Callie to have that juxtaposition between Derek and her family. And it makes you hope that she quickly reconciles this to her way of thinking. 
 Overall, I really enjoyed Borrowed Souls. I feel like we've just touched the tip of the iceberg as far as all the twists and turns that come into play with soul magic. I'm looking forward to witnessing how Callie's strengths and weaknesses come into play as everything continues to unfold.