The Princess Game by Melanie Cellier

 In this fourth installment of the "Four Kingdoms" series, Celeste is struggling with a curse her aunt gave her on her christening day.  Until she was 16 she was above average in both beauty and intelligence.  But on her 16th birthday her intelligence was taken away and she was left as a mindless beauty...or so everyone thinks.  In reality her sharp mind is intact, but the curse prevents her from revealing her true thoughts.  That does not stop her, however, from leading a double life.  By night she turns from the silly princess into the kindom's spy master.  As long as she conseals her identy with masks and costumes, she is free to do whatever it takes to protect her beloved kingdom.  She finds an unexpected ally in a visiting prince and together they uncover a plot that threatens not only her home, but all of the four kingdoms.

I have been really enjoying this series.  The stories only have glancing reference to the original fairytales (this one is based on Sleeping Beauty) but they are fresh and fun.  I like that fact that the different princesses are uniquely flawed. This book also has a pretty well crafted mystery. Cellier was able to stump me.  I didn't figure out who was the real bad guy until nearly the end.  (2018, 314 p.)

Actually, I just realized I have missed one in the series.  I guess I need to go back and read #3 The Princess Pact next.