The basic premise of this story is that there are two types of people - Reds and Silvers. Reds have red blood, no special abilities, and are slaves to the silvers. Silvers have (you guessed it) silver blood, all sorts of special abilities - like super strength, water powers, fire powers, basically whatever you can think of someone has it - which give them all the power in this society. Also, there's a big war that's been going on for a hundred years with a neighbouring country, and thousands of Red lives have been sacrificed over the years due to the conscription of every Red who turns 18 and doesn't have a job. 
 Enter our hero, Mareena Barrow! A seventeen-year-old girl who doesn't have a job, and so she steals from all the people in her neighbourhood (who are just as poor as she is) and helps to support her family - which, if you think about it, means she's actually a really horrible person. But it's ok! She's our hero! We forgive her everything! 
 She has three older brothers who have all been conscripted, and she has resigned herself to her fate until her best friend loses his job and is conscripted. To stop this, she comes up with a plan to escape with her best friend, which involves having to steal a lot of money from Silvers. Obviously, this is very dangerous, and a terrorist attack by Reds thwarts her plan and ends up ruining her sister's sewing hand (she has a younger sister who is a very good seamstress, and is about to make a lot of money from it, but alas, it is not to be). Then, she goes on a stealing spree in her local pub, until she steals from the wrong man and is caught, she tells him all her sorrows, he gives her a bit of money, walks her home, and that's that. Again we forgive her. 
 The next day palace guards appear, and she finds out she's been given a job as a servant there, and then she finds that the guy who helped her out the night before is Prince Cal! Yay, she didn't have to change her ways at all, a man saved her! And in the process of choosing his wife, she falls on a big electric shield and discovers she has powers over electricity - which is quite fortunate or she would have died. This earns her the apparently terrible nickname little lightning girl...hmmm... 
 Anyway, the Queen makes her become engaged to the second prince, Prince Maven. Who is called the shadow to the flame in comparison to his older brother. Deep-seated resentment on Prince Maven's side to his older brother, poor little princeling. 
 To cut a long story short, Maven and Mareena join the rebels, Mareena and Cal like each other, hate each other, kiss each other, hate each other, etc, Maven and Mareena then fall in love, they start kissing too (at the same time she's still kissing Cal), lots of people are killed. All of this is interspersed with lots of martial training, because even though the nobles don't join the army, they all spend hours training to become amazing killing machines (I know, this doesn't make sense. You would think the less noble Silvers would do all the training and fighting and the nobles would be involved with other things, as they aren't going to war. I think it's to make it more along the lines of Mockingjay and Divergent that these scenes are brought in). 
 By the way, I am SO over strong female characters being incredibly weak and unable to do anything without the love of their life. Of manipulating the people around them by pretending they're in love with them. Of being massive users and actually really selfish and horrible, but being portrayed in a way where that is their only available choice! Actually, you know what, it's not. Rely on yourself! Stop being so dependent on a man! Grow up! Ugh. 
 (view spoiler)[Anyway, eventually the big twist is that Maven - shock horror! - is not actually on the side of the rebels but wants to be king, so he and his mother get rid of the king and Cal and Mareena go on trial. The only surprise is how long it takes for the book to get to this stage. 
 Cal and Mareena feel very betrayed and Mareena decides that she doesn't want to be with either Cal or Maven, even though you can tell she still likes Cal. At this stage was one of my favourite ridiculous lines about Maven "Murder helps him sleep". Ooookaaaayyy 
 Anyway, they go on trial, end up killing their opponents, and then escape with the resistance where I'm sure they will live to fight in another book. (hide spoiler)] 
 So basically, it's a rip-off of Mockinjay and Divergent with a little fantasy thrown in.