A pretty enjoyable ride.
Decker Roberts can tell the truth — that is, he can tell when somebody else is being truthful. Of course, that makes him rather important to a lot of people, including the American NSA.
Roberts also has a talent for teaching actors — even though he isn't an actor himself. Apparently these abilities are somewhat related, but it's never really explained.
The story centers around an online community of "synaesthetes" — people whose senses are somehow intertwined, so that they hear color or feel sound — and it's suggested that Decker's talent is a form of synaesthesia. I struggled to believe this. And it turns out that I didn't need to, as it isn't true. At no point do we ever learn why both Decker and the NSA think it's a convenient cover.
I find it infuriating that this is not a standalone novel. It is largely complete, but it's implied that Decker somehow betrayed his deceased (from ALS) wife (though that may be just his guilt speaking), and it stated explicitly that he's betrayed his son, but neither is explained. And why does a retired cop believe the teenaged Decker destroyed his career?
For failing to write a self-sufficient novel, deduct half a star.
For writing "Decker knew that once Alan Turing's usefulness had ended for the British they literally fed him to the dogs"
, another half-star.
I despise writers who say literally
to mean figuratively
! I am fairly certain the British government has not literally
fed anyone to the dogs since at least the Commonwealth period, but absolutely not Turing.