This book has some fairy tale similarities but Harriet the Invincible is not your typical princess. Her name alone gives the reader a clue there will be unusual things happening. Harriet has a curse placed upon her when she is an infant. The curse is to take place when she is twelve years old. Her parents want to protect her forever. Harriet realizes one day, since she has to be alive for the curse to take hold when she turns twelve she can do unusual things and doesn't get harmed. She fights ogres, rides a quail, slays dragons, and goes cliff diving to name a few of the unusual things this princess does in anticipation of a long sleep.
Harriet's parents wish she was home, safe with them. She does return a couple of days before the curse should take hold of her and unexpectantly changes the curse which then causes a string of actions needed to fix the new curse. There are a few things readers can learn from Harriet the Invincible; your actions and words can discourage people from helping you, you can be brave and make changes even when you have no invincible protection, and teamwork works.
I'm going to need to look at Ursula Vernon's other series, Dragonbreath.