I won't be the first to refuse a rote description of plot and characters. Not only would it potentially give away everything, all the little twists and turns, but I'm not sure if the story can be put into any other words than those Gaiman himself has already used. I don't think it should. There are the strongest female characters I have come across in some time; there is the depth of myth and the weight of the world; there are the simple pleasures - and terrors - of childhood. There were moments of darkness that took me totally by surprise and left me feeling unpleasant and uncomfortable, but reading is not about comfort - at least, good reading isn't - and there were moments so lovely and gentle that the unpleasantness was banished. An example: there is a kitten, and there is something awful that happens to the kitten, but there is another kitten and things are somehow alright then.
This book is much like its titular ocean - much, much bigger on the inside. That being said, it is a quick read (both in literal length and in the fact that you cannot put it down) though I found it a little slow at the beginning. There were a few moments where I was less than enamoured, where I wondered what all this singing praise was about but those passed pretty quickly. It isn't perfect, no. But it is dark, and lovely, and true.