Demon's Law is the second book in the Tales of Bard trilogy, following on from Magician's Law. Paedur the Bard has lost two companions and goes to seek them in the Silent Wood, Kingdom of Death. There he meets with a strange ally, Katani, last of the Katan warriors, who died some five hundred years earlier.

They journey together to see the God of the Dead, Mannam, and discover that he is being threatened by a plot to overthrow him by the New Religion. The New Religion is aided by Mannam's once friend Churon, an old enemy of Katani's and they agree to try and help Mannam against the enemies of Death.

In the World of Men, Kutor is organising an army with the aid of Owen, Weapon Master, and his slave/companion Tien tZo. They intend to overthrow the Emperor Geillard and set Kutor on the throne, reinstating the Old Faith as the official religion and striking a blow against the New Religion.

The Emperor has powerful allies, from the Gods of the New Religion to his loyal advisors, Fodla Captain of the guard, Salier the magician, and Barthus, Hierophant of the New Religion.

Kutor and Owen must rally an army and defeat them without the aid of the Bard, and they aren't sure if it's possible.