If you have not read anything by David Mitchell, you should. And CloudAtlas is a good one to start with. Put simply, the book is about power, our will to power, and where it takes us individually, collectively, and historically. The film trailer shouts out “everything is connected”, a cliché, but the book warrants, may even require, repeated readings. And yes, part of the challenge and fun is figuring out how the stories tie together.
The novel is structured around a set of individual stories or vignettes which take place in different historical periods including the future, centuries into the future. Each story is written in the vernacular of the period including the two stories set in the future.
There is plenty of tense drama, lots of action (hence, the film) and gorgeous writing.