The story is told as an autobiography from a mature, adult-Ben perspective. Because of this, the narration voice is able to provide some analysis of Ben's actions and motives which provides the reader with appropriate depth - or shallowness - of Ben's actions. This is critical to making the story anything interesting or providing any tension, because the child-Ben is a shallow, food-obsessed, graceless girl who delights in succeeding at any resistance to Queen Sofia's attempts to polish her into a princess.
In her own description of herself, Princess Ben is a fat pig. In today's parlance, one might say that she has an "eating disorder" due to Queen Sofia's heartlessness, but the narrator makes it plain that Ben's overeating habits (problems) pre-date her parents' deaths. They also provide some of the redemption later on in the book, when Ben's attentions turn to a completely different set of obsessions.
You see, in the depths of her (redeemably non-stereotypical) exile in her Queen Aunt's castle tower, Ben discovers that she has magical powers. She discovers the secret passageways around the castle, and finds a tower with a spellbook in it that begins to teach her how to use her powers. In authorial brilliance, Murdock does not explain the powers of the tower and its contents. Like children (and like Ben) we the readers are forced to accept that the tower's contents simply are and do what they please.
The love/hate relationship with the next kingdom over the mountain gets old quickly. The plot devices with which Murdock moves Ben to the locations needed for interaction with the "enemy" are rather aged, though her particular flourishes on them are amusing and speedy. I'm too jaded to enjoy the "invading each other's dreams" plot filler at this point, so I must admit that I barely skimmed over the brief dream interludes.
The various foreign personalities are unfortunately limited by page size, so remain far flatter than one might prefer as an adult reader. Murdock does provide a strong nod towards the feminist fantasy crowd with a strong-but-brief rant by Princess Ben regarding how much work becoming an accomplished princess can be.
I will be interested to hear what my niece thinks of this book when I send it to her.