I only read about one-quarter and gave up. I can see that it might appeal to kids hooked on the series, but you have to know most of the preceding books because the back-story exposition is terrible: confused, overly detailed with the wrong details, and full of names of people without any memory "hooks" for a lot of them.
(NOTE these are common failings of series authors, but a good writer will put them in seamlessly and the reader starting midway will still enjoy the book).
The continuity of the story is also dependent the reader having on a broad knowledge of both Disney theme parks and associated cities (presumably from earlier books).
I might have followed the story anyway, but was put off by the constant POV-first-person switches (sometimes less than a page) retelling the same event from different eyes without any appreciable difference in understanding.
The plot is a tween romance (despite the age of the characters). ( )

The Syndrome is a short story in the Kingdom Keepers series told from the Farlies (Jess and Amanda's) point of view. Finn and the gang have gone into Sleeping Beauty Syndrome (SBS) and are being hunted by the Overtakers. Jess, Amanda, Mattie, and Wanda unlock clues that help to rescue the Keepers, although they are hampered by the Keepers' parents and the Overtakers. This is a quick read for fans of the Kingdom Keepers series. ( )