The Empire has returned to power, using ancient technology to genetically engineer dragon-like bio-engineered weapons called dragonmares. A young girl, Orta, has lived all her life in a tower in a valley, imprisoned by the nomadic Seekers, who fear she is a harbinger of doom. One night, the Empire attacks the valley with its dragonmares, destroying much of the city. Before the dragonmares can harm Orta, a mysterious dragon appears and eliminates them.

Orta flees the valley on the dragon. Evren, a general in the Imperial Army and leader of the dragonmare squadron, pursues her. She is saved by Abadd, a renegade imperial drone. He flies away and Orta asks the dragon to follow him. In her search, Orta meets Mobo, a friendly but reckless member of the wormriders. Mobo leads Orta through a river valley and a sea of ash to the wormrider village. The imperial fleet attacks the village and Evren's squadron engages Orta, but she and the dragon defeat them. Evren's dragonmare self-destructs and Orta and the dragon fall from the sky.

The wounded dragon carries Orta on foot across a snowy land until its torn wings regenerate. They fend of an attack from a flying predator, but Orta feels remorse when she sees it has children. Abadd reappears and kills the family with a laser volley. He claims to have information about Orta's birth. They descend into the ruins of a tower and access the ancient information network known as Sestren. Orta finds a message recorded by her mother, Azel, saying that she formed using DNA she recovered from a human in Sestren. Abadd explains that he has learnt the secret of drone reproduction and intends to use Orta's body to replicate himself infinitely and conquer the world. Orta defeats Abadd's avatar and discovers that he is heading for the Cradle, an ancient monolithic artifact above the imperial city. She orders Sestren that she be transported there.

Orta and the dragon find themselves in an imperial research facility. After they destroy several experiments, including dragonmare embryos, the facility collapses. They destroy an imperial defense unit and the Emperor dies within the explosion. The Cradle breaks free, destroying several Imperial ships and sending the dragonmares berserk. The wormriders, led by Mobo, attack the imperial fleet at the city, leaving Orta to fly towards the Cradle.

After destroying the last of the dragonmares and the Cradle's shell, a cocoon-like object emerges from the Cradle's core. The cocoon erupts into Abadd's enormous dragon, which Orta and the dragon defeat. The dragon, severely wounded, flies to the ground and dies. The war over, Orta walks towards a mountain range with a baby dragon.

Iva's Story