Low on fuel and hunted by the Fleet of Knives, the sentient warship Trouble Dog heads to the Intrusion - an area of space where reality itself becomes unstable. But with human civilisation crumbling, what difference can one battered old ship make against an invincible armada?

Meanwhile, Cordelia Pa and her step-brother Michael eke out their existence salvaging artefacts from an alien city. But when Cordelia is snatched from her home, she begins a journey that will help her understand the strange songs she hears in her head and the strange things that happen around her. What extraordinary affinity does she have for this abandoned alien technology, and how can it possibly help the Trouble Dog?