The problem with good science fiction is that it’s rarely good for long. Too often an excellent premise builds a brilliant plot predicated upon its sci-fi nucleus, only to dissolve into silliness by the third act. China Miéville’s newest, Embassytown, is the victim and the crime: it’s two-thirds great. Like the best of the genre it begins with a great idea: What if there was a language that could only be spoken with two mouths? In the far future humans trekking across the universe discover a race of beings who do just that: speak in a dual mix of synchronous voices. What’s more: this language is incapable of communicating falsehoods. Incommunicado until they learn to breed clones who can speak to the alien race, the humans follow the path too often traveled – the path toward manipulation. It’s hard to recommend a book that dissolves into silly plot wrap ups by the end, but Miéville excels at creating worlds so immersive and bizarre that the first 200 pages are worth it. Without devolving into trite descriptions of alien bodies or the color of two-star sunsets, a deft plot is woven from a heady concept. Too bad the conclusion falls short.