So here's Reva, an assassin with the ability to see and move between different realities, what she calls moving across "Lines". You can see how the ability to pick a line where that guard's back is turned, or her target takes a stroll down an empty alley, rather than using crowded public transportation could come in handy for killing people undetected.
Anyway, Reva buys some supplies for a hit from a new smuggler, takes a liking to the smuggler, and things rapidly go downhill from there. The smuggler attracts the attention of an undercover member of the galactic police, who is also rather curious about Reva. The smuggler also raises the ire of some of the more established criminal elements, leaving Reva uncomfortably close to that bullseye. Oh, and Reva's own activities have set a bounty hunter on her.
Mainline is a sci-fi suspense story, but it's more suspense than sci-fi. There are certain science fiction concepts in there, like psi-talents and creatures that exist in hyperspace, but the story is more concerned with the problems associated with moving contraband goods past law enforcement, or getting payment from ruthless customers. Which isn't necessarily a bad thing. At least some of the books in Asimov's Robot series were detective stories with sci-fi trappings (that's how I remember the ones I read, anyway). In the case of Mainline, though, I was more interested in the reality jumping than the lack of business ethics displayed by large criminal organizations.
Which is probably why it took me four or five days to get past the first 50 pages. When it became clear the story was going to focus more on Reva forming a bond with the smuggler, I struggled with whether I cared enough to keep reading.
Two other thoughts. In this book's universe, people who are identified as having mental talents are forcibly sent to an Academy of Applied Psychonetics, where they can be taught, and the Academy can "investigate" their powers. Which almost certainly means they're stealing genetic material and creating super-psi-talents. It gets better. The psi-talent is branded with a mark on the forehead to identify them as having psi-talents, and if they refuse to work for the Academy, they're either imprisoned, or have to take drugs to suppress their powers.
All I could think was, "Tony Stark would love these people." I know we're six years and at least one complete mind reboot past that for Stark, but if Marvel didn't want people to think of Iron Man that way, don't let Mark Millar write him punching Captain America, throwing Speedball in Negative Zone Jail, and generally behaving like a fascist.
The other point relates to the bounty hunter. Yavobo seems like one of those stereotypical characters from a warrior society who believes in honor and debts, maybe too smart to be the "noble savage", but in that vein. But for as much as he criticizes pretty much everyone he meets for being without honor, we're talking about a guy who hijacks a space yacht, by threatening to blow up the man's family, then once safely off-planet, throws the man out the airlock. So maybe Christian meant all the stuff about honor to be a load of crap. That Yavobo, like Bane, believes himself to be a righteous man, but he's really just a murderous thug.