With the Chinese government’s crackdown on private investigators, times are hard for those in the business: Which includes Inspector Chen’s good friend Old Hunter.

So when one of Shanghai’s most successful businesswomen asks Old Hunter to help a man nicknamed X who’s been vanished by the government, reason unknown, he accepts the politically dangerous—but extremely well-paid—case, and immediately turns to Chen for help in turn.

What crime has the vanished man supposedly committed? Chen plunges in, his investigations soon leading back to the massacre at Tian’anmen Square, when X spoke up against the Party—and Chen did not. And as the inspector uncovers the life of a man whose background and tastes strangely echo his own, he becomes desperate not just to save the mysterious X, but to redeem himself for his own mistakes.