A Court of Thorns and Roses, book 1, had a "and they lived happily ever after" ending to a Beauty and the Beast-themed YA fantasy. The hero in the first book felt weak to this reader with a much better fleshed out anti-hero. In A Court of Mist and Fury, we see what ever after looks like for the heroine Feyre. Her former 'Beast' hero Tamlin, High Lord of the Spring Court, is just as broken as Feyre after events that occurred at Under the Mountain in ACoTaR. We learn more about Tamlin and Spring Court Politics. Feyre's pact with Rhysand, High Lord of the Night Court, we learn more about Rhysand. The most interesting character remains Feyre - her nightmares, her shame, and her untapped gifts that set her as a future force to be reckoned with.
How the story unfolds felt natural and true to the characters. This book is loaded with tension, internal and external conflicts, so much character development, and it moves at a rapid pace despite the length of the ACoMaF (624 pages)! (I bought this hardback book at Target for the 'Exclusive' short "Wings and Embers" about two secondary characters, which adds 15 more pages of yummy goodness!) I highly anticipate the next book in this series and despair at another year of waiting.
One last thing - this book did not feel like a YA, which is unlike the A Court of Thorn and Roses. The themes are mature as well as the characters.