The fourth book in the Onyx Court series is set in 1884, over a century after the previous book in the series. Like its predecessors, With Fate Conspire can be read as a stand-alone--but reading the other books gives the reader a deeper understanding of the characters and the setting. The mortal characters are new, but most of the immortal ones return from the previous books.

In 1884, the Inner Circle of the London Underground is being built and a few malcontent Irish are bombing London. Because of the large amount of iron in both the tunnels and the trains, the faerie hall is falling apart. Some of the fae have already abandoned the Court and fled. Some, however, remain in the Court while it still lasts.

Eliza O'Malley is a poor Irish girl. Her childhood sweetheart, Owen Darragh, was abducted seven years ago by fairies, and Eliza feels that her own time is running out. She has devoted her life to finding Owen but so far has not succeeded. Nobody believes her story, so she has to investigate alone. She has discovered that faeries are helping the Irish throw bombs; because she was near one bombing, she has become a suspect. The police are looking for her, which makes looking for the faeries difficult. She sees an ad about the London Fairy Society and decides to try her luck there.

Dead Rick is a skriker, a shape changer and a death omen for mortals. For the past seven years, he has been forced to work for a cruel and powerful faerie called Nadrett. Nadrett calls Dead Rick his dog and uses Dead Rick as his errand-boy and a slave to do any nasty thing Nadrett wants done. Dead Rick is neither cruel nor evil; he's just trying to survive. He resents the things Nadrett forces him to do, but Nadrett has power over him. Then Dead Rick gets a chance to remove Nadrett's hold on him and perhaps get a revenge, too. In return, Dead Rick has to ally himself with an unknown fae.

The Onyx Court in With Fate Conspire is quite a different place from the three previous books. The Faerie Queen Lune has vanished, and her subjects are losing their faith in her and her mortal consort, the Prince of the Stone--currently Benjamin Hodge. In fact, Lune is fighting to keep the Court together. We see a few brief glimpses of her pain as the iron rails invade the faerie realm. Hodge is also fighting to give Lune strength. He still has a few faerie knights on whom he can rely, and the few faeries who work in the Galenic Academy are also his allies. The true power in the Onyx Court has shifted to the Goblin Market, where desperate faeries scheme, ruled by cruel and greedy masters who keep humans in cages for entertainment and because the humans can be forced to tithe bread. Some desperate fae even attack humans and prey upon each other. Most are looking for a way to escape.

With Fate Conspire is fascinating mixture of faerie magic and technology began in the previous book, A Star Shall Fall. The fae in the Galenic Academy are still researching different technologies and aether, which works in the faerie realm but not in the scientific human world.

The characters are complex and entertaining. Eliza and Dead Rick are the major point-of-view characters, but short sections are seen from other people's point of view, as well. The faeries who have been in several books are perhaps the most complex, but the new characters are well-written, too. Dead Rick is quite endearing with his struggle to survive and escape from Nadrett's power. His circumstances and struggles mirror the struggles of the Court and the faeries around him. In contrast, Eliza has to work alone; nobody will believe her story about faeries. It has taken a toll on her; she is suspicious of everyone. She has also done her best to hide her Irish background with a false accent and false names.

Brennan draws a great contrast between the servants and the people they serve. Most of the human characters are poor, like Eliza, a refreshing change in a fantasy genre which usually centers on nobility or royalty. The poor folk around Eliza neither glorified nor depicted as evil or incompetent. Like the ordinary faeries in the crumbling Onyx Court, they are just surviving the best they can in a harsh society. Brennan has researched historical London extremely well, and her web site carries a research bibliography.