The Silver Chariot Killer

It's like Bogie said: When a man's partner is killed, he's supposed to do something about it.
Actually, Cletus Berry was just Lindsey's roommate for a couple of training seminars, but all the same, they were good friends, and when Cletus is found shot in a Manhattan alley, Lindsey's going to do something.
There aren't many clues in the ice and grime of Hell's Kitchen, but Lindsey doesn't give up easily. He follows a lead to an antique toy chariot that once was Julius Caesar's plaything, and now that toy is taking him for a marvelously readable ride through New York's dirty streets and Rome's underground, into the worlds of high art and politics.