The Demon and the City by Liz Williams

With Detective Chen on vacation with his wife in Hawaii, Zhu Irzh, his new colleague seconded from Hell, must take over his job and investigate the strange happenings from Singapore Three Police station.

When a partygirl heiress ends up murdered, Zhu Irzh is called to investigate. And when the body disappears from the morgue, Zhu has more suspects than he can shake a stick at, including her sometime lover, Robin Yuan, a less-fortunate girl taken under Deveth Sardai's wing. Even Deveth's rich family is interested in Robin, hoping she might know where their daughter has gone. Neither know she has been murdered yet.

More interesting is the place Robin works for. Her employer, a businesswoman named Jhai Tserai, is doing experiments on demons. Or, at least one Demon, actually. The one Robin is charged with running the experiments on: Mhara. Mhara seems surprisingly nice and gentle for a demon, with powers that allow him to see the future, and Robin has been feeling bad about her job for a while now, so when she seems to be dying after a visit to Deveth Sardai's parents, she decides to free Mhara as her last act of kindness. Mhara immediately repays her by choking her, and she passes out.

Surprisingly enough, Robin wakes up in the infirmary. Surprised not to be dead, she learns that the "Headache tablets" she took from the Sardai's home are actually pills that make one seem to be ill with a fashionable wasting disease, tuberculosis. Though they mimic the symptoms of the disease, she was not actually sick, but letting Mhara go gets her in trouble with her boss, Jhai Tserai, to whom he was a valuable tool.

Zhu Irzh investigates another crime at one of Jhai Tserai's properties when something makes him lose control and he nearly kills a Feng Shui practicioner who irritated him. While Zhu might have found him irritating, he is suprised to find that he nearly killed the man, as it represents a troubling loss of control. Zhu is imprisoned by one of Jhai's security forces, but is freed by Jhai herself after showing the security forces why imprisoning him is harder than it looks.

Jhai and Zhu Irzh have formed a connection, and he convinces her to meet him, where they end up becoming lovers. What surprises Zhu most is that Jhai is a hell-creature herself, though not from China. She is a Deva, an Indian Demon, and can take on an ordinary human form. She has been suppressing her true form with certain neurotransmitters, damping down her emotions, for these lead to her change. Zhu tells her that she can achieve the same effect by having good sex, and offers himself to her for now.

But Jhai has bigger plans then just to become the head of a powerful company on earth. She wants to ascend to the Heavens, because in Hell, she will just be another exotic creature to become a prostitute. She is upset with a world where women are discounted and made to be just an adjunct to men. She wants to bring down the heavenly bureacracy and institute a new order where women can be equal to men. To do this, she has formed a new disease with which to infect heaven, and Zhu Irzh had gotten a taste of it, the symptoms of which made him attack the Feng Shui practicioner.

Mhara, Jhai's former prisoner, is no demon, but a heavenly creature, the son of the Emperor of Heaven. He has reunited with Robin, and they are trying to get to heaven so that Mhara can prevent his father from cutting off the heavenly realm from the earth. His father is tired of the humans constantly falling and ending up in Hell and wants to close off the realm of Heaven. Mhara, who had come to Earth to get an idea of what humans experienced, wants to prevent this from happening. Heaven has no idea what humans go through on a daily basis. Virtue seems easy in Heaven, but thanks to the torture Mhara has undergone, he has a more understanding and merciful view.

Jhai hasn't been alone in her plans. The murdered woman, Deveth Sardai, was in on Jhai's scheme, as was a goddess named Senditreya. When Heaven finds out, Senditreya is cast out, and the Gods seek vengeance. But Senditreya isn't going to go quietly, and since she controls the many lines of Chi, the Meridians, that flow through the city. With Senditreya in a rage, the Meridians are pulling from their places, causing chaos and disorder throughout the city. And the sight of a goddess in a chariot being pulled by two enraged cows causes just as much havoc as the disrupted Chi.

Zhu, Jhai and a returned Detective Chen, along with Mhara, Robin and a dispossesed Feng Shui practicioner must do the impossible: defeat the goddess Senditreya and return order to the city. But do even they have the power to do the job?

This was an excellent follow-up to "Snake Agent", the first Detective Inspector Chen novel. Zhu Irzh is a fascinating character, for he does things very, very differently than his human partner. And with Chen gone on Vacation for a good portion of the book, we get to see how Zhu operates on his own, and manages to piss off his human superiors. Also introduced is the character of Jhai Tserai. Though she is the villain for the main part of the book, eventually, she takes a back seat to the goddess Senditreya, and is a part in taking the enraged Goddess down.

We get more of a look at the Chinese afterlife, this time of the Night Harbor, and what happens to people who can't move on to either Heaven or Hell. Well, can't or won't. And we also get to visit Heaven, and we get to see a living human, Robin, visit heaven as well, as she can experience the place through purely human senses. Mhara, too, is interesting, as he and Robin end up falling in love over the course of the book. But, of course, a relationship between a human and the son of the emperor of Heaven is forbidden, isn't it?

Anyone who enjoys fantasy or detective stories with fantasy thrown in will love not only this book, but the entire series. I am looking for the third book, "Precious Dragon" now.