London is living through one of its darkest times – a comet has just missed the Earth, leaving the city in chaos and the people fearing an apocalypse. Tersias, a blind boy oracle, has predicted the comet and sees visions of the future through the darkness. As Tersias's powers strengthen, people who seek to use them are drawn from the shadows: Malachi, a charlatan magician; Jonah, a desperate highwayman; and Lord Malpas, a keeper of mysterious powers. But none of them are aware of a much darker force that torments Tersias's soul...