Beginning with Episode 4, the show goes off book; the central idea and, I assume, the big finish remain the same but the last three episodes are new material in the
spirit of the novel but not from it. Episode 4 (which was astonishing) explores Laura's story; Episode 5 is a reboot of something that is from the book, but changes key details; Episode 6 is completely new.
The writers are having fun and it's all very Gaiman-esque still. Like
Legion, though, it's clearly going to be a show where you have to be comfortable with not being entirely sure WTF is going on.
In other news, Sense8 got suddenly better again with Episode 6, so I'm hoping the rest of Season 2 will match Season 1's brilliance.
~Boar