Battered, heart-broken and with infected amongst them, the main group begins the long journey south to Melbourne in pursuit of serum supplies and passage towards a safer life beyond. In the heart of the city, Dylan's sister, Lauren, battles to unite the last fragments of a fractured group, fighting starvation and enemies both living and dead. Meanwhile, Jacob leads a handful of survivors south following the Campbeltown massacre. At every turn, separate forces plot against their objectives. As the invasion grows stronger, the intent of the threes becomes clearer and what awaits the converging groups in Melbourne is far worse than any of them could have imagined...