Because Zyerne’s spells broke King Uriens’s mind, Gareth becomes Regent of the South and sends the garrisons, and the strong rule of royal law, that he promised. For four years, another of Gareth’s royal cousins, Rocklys of Galyon, commands the garrisons of the North. Then Rocklys is convinced by an old suitor of hers, the wizard Caradoc of Somanthus Isle, that Gareth is incompetent and that she, Rocklys, would make a better ruler, and it is at this point that the book Dragon-shadow begins.
Unbeknownst to anyone at that time, Caradoc has been possessed by a demon named Folcalor, who seeks to gain mastery over the human realms of the earth by setting up Rocklys as a pawn. Folcalor, in Caradoc’s body, summons other demons to possess the bodies of wizards and dragons, forming an all-powerful corps to lead against Gareth. One of the first wizards seized by Folcalor is John and Jenny’s twelve-year-old son, Ian, taken when Jenny herself is away from home helping one of the garrisons deal with bandits. After desperately trying to get in touch with Jenny, and failing, John goes to the Skerries of Light, the islands in the far western ocean, to seek out Morkeleb’s help.
From Morkeleb he learns that exactly the same situation occurred a thousand years ago. Though ordinarily demons can be controlled by wizards with ward-spells, then—as, suddenly, now—demons acquired unheard-of powers, and, led by a demon-ridden wizard named Isychros, possessed both wizards and dragons to take over the ancient realm of Ernine. Folcalor, and his master, Adromelech the Arch-wight, were called in by the ancient wizards of Prokep to defeat the demons ruled by Isychros, demons who were banished behind a mirror wrought of indestructible meteor-iron. When the demons within them were destroyed, Morkeleb says, the wizards and the dragons all died.
Desperate, John and Jenny go south, to both warn Gareth and rescue Ian. Jenny discovers too late that the demons trap wizards through their magic; that in using her magic, she makes herself vulnerable to possession herself. She is possessed by a demon named Amayon, while her true soul is imprisoned in a green crystal that Folcalor is keeping—unknown to his King Adromelech—for secret purposes of his own. In trying to free her and Ian, and the other possessed wizards, John and the gnome-witch Miss Mab go to Ernine, and John passes beyond the Burning Mirror into the Hell that lies behind it. There he makes a bargain with the Demon Queen for the spells and the implements that will free the possessed mages from the demons’ influence. In return she demands a teind, a tribute: a piece of a star, the tears of a dragon, and a gift freely given to him by one who hates him. If he cannot bring her all three, he will become her slave in Hell.
Though John eventually tricks the Demon Queen and wins back his soul from danger, he is branded a trafficker with demons by Gareth’s councilor, Ector of Sindestray. The spells he obtained from her free the wizards Folcalor has trapped. In pursuing Folcalor—still in the body of the mage Caradoc—Jenny and Morkeleb slay Caradoc beneath the sea in a battle whose virulence strips Jenny of her powers. Morkeleb cannot help her, for between his love for her and his own battles with the demons, he has renounced most of his own magic, as he once renounced the gold to which all dragons are addicted. He has passed beyond material existence and become a Dragonshadow, a creature of the legends of the dragons of whom few mortals have ever even heard.
The demons appear to have been defeated, but the psychological toll on everyone concerned is devastating. Jenny and Ian—and the other surviving wizard of Folcalor’s corps, Bliaud—discover that once one has been possessed by a demon, one is plagued by desperate feelings of longing and grief. At the outset of Knight of the Demon Queen, Ian begins to hear the demon Folcalor whispering to him in dreams, trying to take him over. He tries to kill himself to prevent this from happening, and John and Jenny, their love strained to the utmost by the emotional aftermath of what they have been through, quarrel. Jenny returns to her own small house on Frost Fell, where she lived alone for many years before living with John; John nurses Ian at his castle at Alyn Hold. Through the bitter weeks of winter, Jenny wrestles with the worst of her depression and dependence on the memories of the demons.
Before Jenny can return to speak to John, John is visited by the Demon Queen, Aohila. The Queen extorts his services in looking for a man who, she says, betrayed her. She sends him on a quest through various Hells, with Jenny’s former possessing demon, Amayon, as a guide. In freeing Jenny, John captured Amayon and turned him over to Aohila for torture and vengeance; Amayon is an equivocal companion at best.
On her way to Alyn Hold, Jenny discovers that the demons, far from being gone, are growing in numbers, possessing the bodies of the dead. They are also buying slaves from the gnomes, slaves who have no apparent use in the gnomes’ mines—John was warned of this earlier by a former mine-slave named Brâk, whom he helped to free on his way to the Skerries of Light. Realizing that Folcalor is still at large and still plotting, Jenny and Ian seek to retrieve the talisman jewel that still holds the soul of the mage Caradoc, which was lost in the sea during the final battle. Though the whalemages bring it to her, Jenny is forced to drop the jewel, which falls back into the sea and takes over the corpse of a drowned sailor. In this corpse, Caradoc attempts to drown Ian so that he can take over the boy’s body and thus have the use of his magic. Jenny drives him away, and he flees.
After passing through several Hells, John comes to another world, where magic does not work and where Aohila’s betrayer is hiding. He is a scientist of ether physics named Corvin NinetyfiveFifty, and demons working for both Folcalor and Folcalor’s ruler, the Arch-wight Adromelech, are hunting him there. John falls in with a group of men and women, the League of the White Black Bird, who claim that they would be wizards if magic existed. One of them, Shamble, gives him a sword, which he says is spelled against demons. John knows that this world is a true world and not simply another Hell, because the stars are the same, including a comet that has appeared, which is called the Dragonstar, and that appeared also in the sky a thousand years ago at the time of the demon-wars in Ernine.
Returning to Alyn Hold with Ian, Jenny finds the place besieged by bandits who have allied themselves with demons. Because the demons can use a wizard’s magic against him, Ian cannot use his own magic to keep the Hold from being destroyed. Jenny and Ian, at a safe distance, use Ian’s magic to transform her into the shape of a dragon, which Morkeleb once showed her how to do. In this shape she drives the bandits away, but in becoming a dragon she is in danger of forgetting her humanity. Returning to human shape nearly kills her, and she is healed by Morkeleb. The Dragonshadow takes Jenny south to Bel, to warn the regent Gareth that the demons are taking the bodies of the dead.
They arrive to find the city in the grip of a terrible plague. Gareth’s wife, Trey, dies, and to Jenny’s horror is resurrected by the wizard Bliaud, who, weaker than Jenny or Ian, has given in and accepted another demon into his body and mind. Trey’s body is the possession of a demon; when Jenny goes to the Deep of the Gnomes to consult with Miss Mab, she is cornered by demon-possessed gnomes and shot with a poisoned arrow.
At the same time John traps Corvin NinetyfiveFifty in the magic box that the Demon Queen gave him for the purpose. But because he doesn’t trust Aohila, John had the League of the White Black Bird manufacture a duplicate box, with a magical gateway between the two boxes. Upon his return to Bel, John is betrayed by Amayon and captured by Ector of Sindestray’s men, and condemned to be burned at the stake. Gareth, exhausted and shattered by Trey’s illness, death, and resurrection, promises John that he’ll be broken out of prison and smuggled out of the city, but the demon Trey drugs Gareth, and the plan is not carried out.
THE DEMON QUEEN came in the dark hours before dawn; she shined in the blackness with the moony radiance of rotting wood.
Chained, John Aversin raised his head and squinted at her; his breath came fast. The King’s guards had taken his spectacles from him when he’d been brought to the cell beneath the prison tower, and even at three feet—the cell measured barely six—she was blurred to him, which made him sure that this was no dream. That fact was perhaps the most frightening of all the things