Wow!, I thought, just my kind of thing; time quirks. The quirk in this case is little patches of time runing differently, and there are all manner of weird things going on, most of all some kind of leak which the Doctor has to stop or something... I personally found it all rather confusing, what with these strange (and atrange doesn't necessarily mean bad) aliens who I could never quite fully believe in, and then the standard separation between Doctor and companion.
It's a very depressing book, lots of horrible thngs happen and it all looks like it's going to turn out horribly, and indeed all is not well at the end of the book. However, that's to be understood as it is, after all, part one of four of this Sam-is-lost arc, the rest of which is absolutely brilliant [Legacy of the Daleks is next, then Dreamstone Moon, but Seeing I, next, is top!], and so whilst not being a brilliant novel, it serves a purpose.