Mercy Chan is a woman who's rarely given a second glance, unless her only talent is desperately needed. She's grey, short, plump, and middle-aged but Mercy has an essential skill. She can talk to ghosts.

The place where she lives keeps her busy. Thirty-three years ago she showed up in Kowloon Walled City, with no memory of her past and uncertain that she would survive her present. But "Kowloon," as the residents call it, has no shortage of ghosts and many of them are unhappy, vengeful, and violent. Exorcists often fail to expel them but Mercy can understand them. In conversations, she learns what troubles these specters and helps them achieve peace. But these achievements are usually accompanied with grisly, deadly forms of revenge, giving Mercy a notoriety that brings her to the attention of the leader of the Snakeskin Triad, Cobra Lily.

Being no fool, Cobra Lily swiftly realizes Mercy's uses and takes her on as an employee. LIfe goes well for both of them as long as they stay behind the walls of their city. But outside those walls, Hong Kong is steeped in the modernity of 1975 and Kowloon Walled City is a large blemish on the image of that metropolis. When Cobra Lily discovers that there are plans to demolish "Kowloon," she marshalls her legal defences and confronts the Hong Kong Executive Council. This decision brings supernatural forces into play, most notably one that not even Mercy can't reason with.

Thousand-Faced Girl has no need for Mercy's understanding. She has found a way to exert power in the mortal world as well as in the realm of spirits. For the past thirty-three years, she has taken on the form of the bodies she has killed, inhabiting them for a while, then finding another. At the moment that she and Mercy meet, she has claimed the body of a leading member of the Hong Kong Executive Council and with that, she has devised a deadly fate for that city and all who live in it.

Why is this spirit intent upon revenge? Why is there an eerie form of recognition between her and Mercy? Who is the villain of this story? What does Mercy fail to remember?

A strange set of truths pervades this novel, a code that posits a frightening philosophy. Humans feel no true sympathy for pain unless they experience it for themselves.People who have no sympathy cause the most suffering and they can't comprehend the pain they cause others. The only way to create understanding is through vengeance, by spreading pain to those who only cause it but never feel it.

"Do you like ghost stories, little sister? Sit down, get comfortable. You haven't heard this one before." These three sentences form the prologue of Sunyi Dean's novel--and she's right. Ghosts appear often in fiction from Asia, observing no national boundaries. But in The Girl with a Thousand Faces, there are two ghosts whom many readers will never have encountered before, in a story that the author says "is a love story to Hong Kong's ghost legends." Or are they legends? And do we need them now?