The Imperial forces led by Gaius have begun to move against the castle of Avalon. As such Arawn decides it is necessary to form an alliance with the neighboring Brigantes Tribe. However, when they arrive they meet Taliesin, and it emerges that the Brigantes Tribe's Chief is dead and there is no successor to take his place, because of a prophecy claiming that the next Chief will "...offend the Heavens...be cast into the Darkness...and be devoured by a monster...".

On the third day the battle grows hotter. Riannon swears an oath on the scarf she gave to Arawn, to protect him with her life. Arawn has healed, but hasnt woken up. He sees first Myrndill, then Pwyll and Primula in his dreams. They all show him the valour with which his comrades are fighting to defend his city, Avalon. Both Pwyll and Primula assure him their deaths were not his fault. Gaius's seige towers keep proving innefective, as Lyr and Rathty have now got Morgan and Octavia to help them. He then launches the battering ram, after gainng control of the drawbridge. Riannon draws everybody back to the inner city walls to continue the defence. The battering ram breaks through the main door, and Gaius attacks in full force.

Arawn becomes the 12th Angel to replace Myrddyn but he leaves Heaven after realizing that the other Angels have placed humanity under mind control again. He then frees Primula but as a result is cursed by the other Angels by being banished from the Heavens and losing his light. After seeing Arawn's past, Taliesin knows what he has to do. After parting with the baby dragon and leaving the cave, Taliesin gets his first look at the enemy. Elsewhere Arawn and the others defend the giants as they try to start an avalanche. Immediately after the avalanche starts, it is stopped by the snowstorm picking up. Realizing the Spirits are behind the snowstorm Arawn decides they will have to face the enemy at the foot of the mountain. Taliesin then uses the Song of Creation to end the blizzard and starts a new avalanche, destroying the Dark Army, but is seemingly killed.

When they reach the top floor, they are surprised to see a beautiful garden. Riannon feels a cold presence despite the beauty of the garden. As they go further, they notice the Emperor's corpse sitting at the center of the garden, and then a voice greets them. They are shocked to see a figure in white before them. Ogam realizes that Lector the Astrologer from the Emperor's Court is the Lector, one of the 12 Angels, and the one who killed Arthur's father and framed Arawn for it. Arthur uses Dyrnwyn to destroy the Garden, which is revealed to be an illusion. A passageway to the Heavens opens, and Skeleton Warriors attack, but Arthur and Arawn manage to attack Lector. Arthur manages to wound Lector, making him furious and consequently summoning Merkadis. Ogam tells everyone that Merkadis is the one who killed Arawn before. Lector then becomes one with Merkadis. Arawn and the others are nearly killed when Merkadis destroys Palladium, but are saved by Taliesin and the Dragons.