Cirrus@Austlit

After a flu sweeps the country and leaves most of the population dead, Georgie cares for her two younger sisters and worries for their cystic fibrosis: Annalee had lung transplants before the epidemic and only needs medicine, while Eliza is severely ill. They stay in their house, self-quarantined.

A call comes from the hospital, informing them they have lung transplants ready for Eliza. The sisters travel into inner Melbourne, where they meet a girl, Mari, with an unnamed baby. Mari leaves the baby with them and commits suicide as they're about to reach the hospital.

The hospital is bombed-out, and Eliza reveals that the phone call was a recording she kept from before the epidemic. Annalee is growing more ill as her body rejects the lung transplant, and they're running out of medicine. Eliza faked the calls to get them out of the house. As Georgie begins to despair, the phone rings.

After the 'Pulse' destroys most things electronic and electric, Jin and Aisha are two teenagers scavenging together. Jin specialises in batteries, Aisha in pharmaceuticals; Aisha's mutism relieves Jin of having to keep his hearing aids on.

While preparing for the next market to trade for food, they meet a third boy, Billy, who Jin starts crushing on. After a misunderstanding at the market, Billy and Aisha - who can speak and simply chose not to - reveal they knew each other, and moreover, knew the origins of the apocalypse.

Billy and Aisha questioned their world before the Pulse - the android-like plastic foster mothers, the lack of humans besides teenagers, and the city no one has ever left. They discovered it was an experiment, and the researchers ended it with the Pulse. Reunited, the trio plan on going to the laboratory and restarting the city.

When a drone catches sight of a kangaroo, siblings Lexi and Jeff set out to hunt it while their mother stays behind with little Jackie. Lexi's leg is shortened after a bad fracture, slowing her down on the shifting sand dunes; she squabbles with the younger Jeff, frustrated at times by his autism.

They find the kangaroo, but when Lexi startles Jeff into an outburst, they lose it. After Lexi comforts Jeff through a panic attack, she reveals that she broke her leg trying to save Jeff from a bad fall. The siblings reconcile.

The next morning, the first rain in a decade falls, and they find fish in the creek bed where Lexi broke her leg.

Kaye, mother of two, has been preparing for the apocalypse with her friend Micha, whom she met at an arthritis support group. When her communicator wakes her up, she finds out the flooding has begun. She brings her children into a vehicle, a sola-bub, and they make their way to Micha.

Along the way, they encounter difficulties: the sola-bub breaks down once, they pick up a lost child, and they can't reach Micha's base. Instead, Micha deploys a hot air balloon to bring them all to live on a farm.

Tally is one of the patients living at a private hospital's psychiatric ward after the apocalypse. Along with another survivor, Count, she goes searching for supplies. They encounter a nurse, Mary, on crutches in a medical clinic while looking for medications.

Mary joins them, and they use a scavenged ute to carry more supplies. An earthquake has them fleeing home with a narrow escape. Tally checks on the rest of the survivors before gathering them around for tea time.

Skye works on the moon, trying to translate her name into the propagative crystals used to communicate by Moltorians, a mysterious alien species that look like rocks. On earth, after a series of rebellions and wars, Hugo launches humanity's last space voyage for some time to the moon. He plans to learn what happened to the science expedition they sent to communicate with the aliens - and to his wife, Silya.

When Hugo and Skye meet, they realise they are father and daughter. Skye is revealed to have pituitary gigantism and can only live on the moon, never on Earth. Skye withdraws as Hugo solves the puzzle of what happened to the rest of the expedition: killed by Silya's lover for planning to kill Skye, who was eating all the food, while Silya died years ago of kidney failure.

Skye reappears and asks Hugo to check her math for a spacesuit that will fit her. When it's complete, she puts Hugo in his spaceship and bends the airlock, preventing him from coming back. She prepares to go to meet the Moltorians.

Jane survived the plague that killed humanity. Grief-stricken after her parents' deaths, she starts searching for survivors, and eventually meets Sam, a man determined to build a community and find any other survivors. They start a radio show and make their way to Brisbane, which they've advertised as a meeting spot.

On the way, Jane's Crohn's disease flares up, and she's forced to reveal it to Sam. In turn, Sam shares that he had orchitis as a teenager, leaving him infertile. Once they reach Brisbane, they find a nurse with multiple sclerosis, Judith, who hypothesizes only those with autoimmune diseases were immune to the plague.

Jane, an electrical engineer, helps Judith preserve frozen fertilised embryos, ensuring the human race's survival. They head to the meeting spot, where a dozen other survivors are waiting.