This was a fitting end to the story. It starts as a magical heist story, complete with requisite training and preparation segments, but then expands to the conclusion of this series. The action shifts between Earth, Fillory, and flashbacks that fill in portions of the story I've been waiting for and some that are new and also necessary. 
 ***SPOILERS BELOW*** 
 Ultimately this has been Quentin's story, and it is satisfyingly concluded here. He has grown up and become a responsible adult, has learned to mend relationships, and can carry on doing great works of magic. The resolution of Fillory's life cycle and the purification of its godly powers were handled in an appropriate manner that built closure and renewal into the world. Although it's clear that the characters will go on making new and interesting stories, this story is complete and satisfactory. Their lives are now their own.