Spoiler alert: Don't read this if you don't want to know what happens......!
The story commences with the narrator, Karen, a 17 year old, discussing her loneliness and her fears that her isolation is affecting her mental health. Her journal is a means to combat this.

In it she describes how she successfully flees Melbourne for the Mornington peninsula as a global epidemic breaks, but loses two weeks to the illness. She survives and meets Sean, another survivor, who explains to what happened while she was ill. Short of food, they venture out of Sean’s place to the nearest town.

They go to a doctor’s surgery, and have a frightening encounter with a virus-infected nurse. They visit Sorrento, where they are attacked by a dog. Tricking the dog they take off, narrowly escaping a group of infected who converge on them.

Bewildered, they continue to flee, and take refuge in the farmhouse of a market garden. Two feral farm dogs besiege them in the house, A plan to trap the dogs nearly ends in disaster, but shows how brave and resilient Karen and Sean are. The nickname “ferals” is applied to all the infected.

They decide to set up an experiment, which they hope will attract anyone like themselves, but won’t give them away to the ferals. While the experiment unfolds, two more survivors blunder into the story, and Karen and Sean rescue them.

Blair and Sophie tell how they are the remaining two of larger group, and give a chilling indication of what happened to the others. They are locals, and Sophie knows the area well. Sophie guides them to a safe place, the Cape Schank lighthouse. The group gets to know each other. Accidentally triggering an alarm, they attract ferals to the site and are again besieged, this time by hundreds.

Within the safety of the lighthouse, they take enough time to plan the next move, and then cleverly take their leave. The plan involves cutting across the grounds of a luxury golf-course. On the way there they find the body of Gary, who had been part of Blair and Sophie’s group. Blair, bitterly resentful, takes revenge on the ferals.

The golf clubhouse has power, water, some food and is a safe haven, and they decide to stay. They spend the next few weeks securing the area, exploring and collecting useful equipment. When the power cuts out, they realize that many of the advantages of the clubhouse are gone, and they carefully plan an exploratory raid on the town of Flinders, with the Navy base and supermarket key targets.

They tow a powerboat and launch it at Flinders boat ramp, next to the jetty. This gives them the ability to move around, safely, on water, and a safe escape route if the raid goes wrong. Using the powerboat they visit the Navy base, which has been burned to the ground. They also visit the yacht club nearby. They realize that by using the public address system of the yacht club, they can create a diversion and perhaps raid the supermarket more safely. They do this and it works well.

On returning, the weather has turned nasty, and the boat is in danger of being swamped. They decide that rather and leave it to its fate, they will get it out of the water and take it back to the golf club with them. It all goes wrong: they are attacked by ferals, and it is only a driving accident that saves them, in the process ruining the car and destroying the boat. In the panic of escaping Sean is left behind at the Flinders Jetty.

Shaken and injured, they find another vehicle, and go back to get Sean.

They return to the jetty. A frantic episode follows. To escape they have a long swim to a yacht moored by the yacht club, where they find Sean.

They recuperate, and Sean reveals another idea, spurred on by the success of the diversionary tactics at the yacht club. He suggests attracting and trapping the ferals at the nearby football oval. They return to the golf club and spend a number of weeks fine-tuning an elaborate plan.

The trap is set. Part of it requires building a bonfire that generates a highly visible smoke column. Blair muddies the waters by embedding some home-made bombs in the bonfire. This is almost the cause of their death. One of Blair’s bombs causes the entrance gate to be blocked, stopping the ferals from entering the trap. While resolving that problem they are attacked, and a desperate hand-to-hand fight occurs. All of them are injured, but they manage to escape and the plan subsequently works, enticing hundreds of ferals into the ground and clearing out the township.

A few weeks of peace and recovery follow, although it is marred by Blair becoming ill from a bite injury sustained in the fight. They stay on a yacht, offshore to the town, for that time. They visit the football ground and it is apparent that the ferals are all, finally, succumbing to their illness.

Blair reveals the reasons for his personal demons.

His fever becomes a variation of the virus, and for their own safety they are forced to lock him in the boat, so they move to the jetty as a home base. They turn the jetty into an island save haven, burning out part of it so any newly arriving ferals can’t get to them.

Some weeks of settling take place, and they gather resources together. Sean starts learning to use a sailboat, in the expectation they will eventually run out of fuel.

Careful....if you read the next few lines, you'll get to the end....!

Sean talks Sophie into coming for a sailboat ride, and an accident sees them drift off under awful circumstances. Karen pursues them in a small dinghy, but can’t keep up and the dinghy is swamped.

The books closes where it started, with Karen discussing her loneliness, with the feral, imprisoned Blair as her only companion.