Three triplets are born into a harsh world of authority and power. When they turn 16, they will duel each other in accordance with an old custom. Whoever is the last one alive will be the next ruthless queen. Three young triplets being prepared to murder one another. The poisoner Katherine. The elementalist Mirabella. The naturalist Arsinoe. Since their mother passed away, these three have been bred to the point where they have to kill one another to take the throne.

On the island of Fennbirn, there are three triplet queens born every generation; they are all equal heirs to the throne and each possesses a valuable magic. The fierce elemental Mirabella can summon fierce storms or ravenous flames with the snap of her fingers. Katharine can consume the most lethal poisons without even a slight stomach ache. It is said that a naturalist by the name of Arsinoe was able to tame the fiercest lions and bring forth the reddest rose.

However, being the Queen Crowned requires more than simply coming from a royal family. Every sister needs to fight for it. Once they turn sixteen the game of life or death starts. 

The princesses had been dispersed to various places to be raised in accordance with their individual gifts. Since being raised by the Arrons, Katherine has developed a resistance to all poisons. To develop and hone her abilities to control the weather, Mirabella had been sent to a temple. To teach her how to handle animals and the natural world, Arsinoe was sent to a farm. Mirabella eventually grew weary of her life after many years like this and fled to the woods.

A few days after escaping, Mirabella was out for a stroll when she spotted her sister Arsinoe perfecting her skills by a tree. She immediately wanted to conjure a lightning bolt and electrocute her because the sisters had been taught to kill one another. Mirabella was supposed to kill her, but despite knowing this, she was unable to. She conversed with Arsinoe instead by approaching her. At first, Arsinoe was cautious, but she kept quiet because she secretly didn’t want to kill her sister either. After a lengthy discussion, Arsinoe went back to her farm and pretended that nothing had happened, and Mirabella made the decision to visit the temple once more.

The third sister has her mind set in stone, she wants to win this battle. She will not change her mind. Will the other sisters let herwin, or will they only save themselves and carry on this tradition to the next generation?

 Three Dark Crowns is a book about 3 girls forced into a cruel act, trying to differentiate what is right from what is  wrong. Kendare Blake, the author, writes this first book in its series full of thrill and mystery.