Reasonably well illustrated--the lines of the watercolors are crisp, and the faces beautiful, but there seem to be details lacking, as though the artist lacked imagination of what to do with so much canvas. Often I buy children's books for the pictures first, and then the story; this one does not qualify in that regard.
The story is reminiscent of the "The Lion, the Witch, and the Wardrobe," with the king sacrificing himself for an errant adopted princess. In comparison to Lewis' powerful classic, it feels rather empty when the king gets up moments after being supposedly killed--not really dead, but only seeming to have died.
The only message of real power in the story is that the princess is able to find the way back to the castle (hence the name of the story) because the king has come down to save her, hacking his way through the forest (with his armor and sword), so that there is a clear path back to the castle. The parallel with the Savior's sacrifice is clear: we know the way back, because He came down to earth to be among us and save us.
With several better Lucado titles to choose from, this is one book that I would only recommend buying if you can't resist a spiritually metaphorical fairy tale, if there is nothing better available, or if you are intent on collecting all the works of Max Lucado.