The Last Twilight was an action packed thriller that had me sitting at the edge of my seat several times.
Rikki is a virus hunter doing work in the Congo, who unknowingly becomes the target of two different men needing her expertise. Both want her alive and are willing to go to extreme measures to ensure that she's taken captive.
Rikki was a pretty kick ass character. She's emotionally and psychically scarred which has caused her to take a rather jaded outlook on life, but despite her pragmatic approach to things, you can tell she's a compassionate person. Also, despite being the only human in a cast of supernaturals, Rikki is highly resourceful and can hold her own when things start to get dangerous. I always adore the heroines in Liu's books, because they're always well rounded characters who can kick a little butt.
Because of the threat to Rikki, her boss has hired Dirke & Steele to protect her. Amiri, a cheetah shifter, and Eddie, a guy who can light things on fire with his mind, are dispatched for the job. Amiri and Rikki both have some interesting pasts and as they get to know each other, you can see exactly why a connection between them forms. They know how to relate to the other and it's wonderful to see a relationship in a romance where you completely understand why the two characters are drawn to each other.
One of the other things that made this story so compelling for me was the Congo setting. The majority of the action is our heroes running for their lives through the jungle from two different pursuers. The atmosphere of the Congo really added to the suspense, because they were isolated with no way of contacting anyone who might be able to help. The jungle also added a level of creepiness in the "forest has eyes" kind of way. I just loved it.
My only regret is that I haven't read the series in order. I was all over the place with these books, reading the ones that sounded the most interesting to me first. So, while the Dirke & Steel series can be read as stand-alones, I would recommend reading them in order because there's a story arc that runs through the whole series. Unfortunately, some of the nuances of that arc were lost on me because of the way I've been reading the books.