A fitting end to the series
What can I say without spoiling the twists and turns of this book? It's good. Really good. Penny faces not only physical challenges and hazards, but psychological and philosophical ones. She has to literally fight her inner demons and decide who she is. Hero, villain, daughter, friend, girlfriend, icon, force of change... and if she's not careful, winning will lose everything.
Getting into slight spoilers, in this book, Penny is deprived of powers, family, and friends, forced to rely solely on her wits, a handful of allies, a robotic body of incredibly advanced technology, and an animatronic goat. Twists and turns, and a metric ton of callbacks, results in a satisfying finale to the series.