Ico was a 2001 videogame (for the Playstation). I loved it; I still love it. It remains a landmark in atmospheric, engaging videogame storytelling. Notably, it was almost entirely wordless. Everything was conveyed through architecture, lighting, the body language of the protagonists, and -- most important -- the physical struggle of the game's challenges. If you haven't played the game, this makes no sense to you. Let me put forth that the most important button on the game's controller, the one about which the story revolves, is "hold hands".
So how does this experience translate into a novel?
A direct transcription of the game's events would be tedious and interminable. The author, sensibly, has expanded the story in several directions.
So: a young boy mulls his fate. Ico has horns on his head, sprouted on his thirteenth birthday, and that means he is to be taken off to the Castle in the Mist -- a sacrifice to its never-seen master. That much, we knew (more or less) from the game. But the book begins with the village elder, pondering his responsibility to send a student to an unknown doom. And then we meet Ico's best friend, and learn something about why the village has such a horrific custom. Quite a bit happens before the journey to the Castle itself (which is the game's first scene).
Once inside, the narrative hews closer to the game; enough so that readers might be put off by the focus on architecture, and all the scrambling Ico has to do through it. (Interactive fiction fans won't be a bit surprised.) But he soon discovers Yorda, a girl locked in an iron cage in the Castle's tower. Here the author takes her strongest liberty. In the original game, Yorda was seen only from the outside. She does not speak Ico's language; he does not even learn her name for a good fraction of the game. She is not passive, but she is part of the story's enigma.
The book, in contrast, freely switches to her viewpoint. When she and Ico join hands, he gets flashes of her memory -- more of the story's background than the game ever gave us. Parts of the Castle gain unexpected depth and history. And then we move entirely to Yorda's frame. The middle third of the book is entirely her narration, showing us (though not Ico) her childhood in a Castle full of courtiers, scholars, tournaments, and secrets. I found this the most compelling part of the book, no doubt because it was entirely new to me.
(I would be willing to describe it as Yorda's book, with an unusually broad frame story from Ico's viewpoint. Okay, except that the beginning has the elder and the buddy kid also. The structure is hard to get a grip on, honestly.)
Eventually we reach the end of Yorda's episode, and return to Ico -- blithely ignorant of the last 125 pages of narration, and therefore no longer quite our protagonist. He's still the go-clobber-the-baddie sort of character we expect from the game, and so the story wraps up.
The author's interpretation of what's going on is rather different from what the game presents. Thus, her ending diverges as well. Which is fine; I can replay the game any time I want. The tang of familiarity is in the sunlight, the sound of the sea -- the rhythm of two children running along a parapet, holding hands.
And for the reader who never played the game? I can't give you a completely fresh viewpoint; I know the game too well. But I was startled, halfway through the book, by the realization that I was reading an unabashed fairy tale. It's a form that written fantasy (at least, published English-language fantasy) has largely abandoned. We seem to prefer either added grit or the "urban" grounding of the modern world. Ico has an ethereal princess, a sturdy village boy, a curse, a castle, and an evil witch-queen; stir well and swallow in a gulp. There's nothing ironic or fractured about any of it. (Not that I mind those directions either -- halfway through the first season of Once Upon a Time right now, thanks.)
The language is a bit weak, prone to fantasy-conventionality and (as I said) too much physical description. (The text is Japanese, translated to English.) Nonetheless: engaging, moving -- if you're willing to buy into fairy tales -- and a fine addition to the Ico universe.
(No, I don't see anything on the net to indicate she's working on Shadow of the Colossus. I'd read it, though.)