The book starts with our protagonist Steven "Ten" Kampacalas meeting other police officers at a teleport to go to a planet that wants peacekeepers. This planet has the only other intelligent beings that Terrans have found so far, and when their diplomatic delegation arrived on Earth, they were made Silent -- non-telepaths -- because of all the people with everything in their head. As if that wasn't bad enough, a Silent mother will have Silent children.
So now Egar has crimes happening that they can't solve because many of them, they believe, are caused by Silents, and they've asked Earth police to come help. The future Earth is sufficiently violent that the officers have to learn to use other slang and call themselves less violent nicknames.
Ten is trained, makes friends, and finds a place to live. It's a little uncomfortable knowing that your neighbors know everything that's going on in your head. Then again, they're used to the things we'd hide. Ten finds ways to help the Normals and Silents deal with each other (Normals don't usually speak out loud).
Then besides the vandalism and such happening to the Iregara, cops start being murdered. Is it one of them? A Silent? Why would they be killed?
This turns out to not only be a really interesting premise on how telepathy would work and what would happen with non-telepaths, but it's an excellent murder mystery. I recommend it highly.