Leigh Bardugo's "Crooked Kingdom" concludes the story begun in "Six of Crows," which expands on the universe she created in her "Shadow and Bone" trilogy.
"Six" ended on a cliffhanger. After Kaz Brekker and his crew broke a scientist out of a maximum security prison, evil gazillionaire Jan Van Eck reneged on his deal. Van Eck kidnaps Inja to coerce Kaz into delivering the scientist with the secret to the formula to control the mystical Grisha. Kaz sets out to rescue Inja with his remaining crew - a band of misfits, each possessing a unique talent. He also seeks revenge against those who have wronged him.
It sounds complicated because it is. Kaz is a brilliant strategist, but Van Eck keeps thwarting his well-laid plans, forcing Kez to adjust his plans, which causes Kaz to respond, and so on. It is a fun game of cat-and-mouse with many twists and turns.
I do not recommend reading this book except as a part of the duology. Bardugo introduces her characters with little explanation of who they are.
This is the strongest of the five books I have read in this series. Bardugo does an excellent job building a plot with multiple twists and turns. She keeps us guessing as the heroes and villains play a game of mental leapfrog. She creates the characters and the relationships between them, making the reader care about each of them. One by one, Bardugo tells the backstory of each main character introduced in "Six of Crows," revealing their motivation and providing a satisfying depth to each of them.
As a bonus, a few characters from the original trilogy also make an appearance.
"Crooked Kingdom" contains multiple adventures, multiple love stories, and multiple action sequences. It includes joy and danger and a single great tragedy. It is smart, and it is fun! It is a solid finish to this duology.