One day, the power goes off and the world falls silent. And in two very different parts of America, two very different nightmares are about to begin. In Manhattan, Elizabeth and her brother Henry are all alone in their parents' apartment. Looking out the window, they can see the carnage slowly spreading through the city. But as hopes fade for their parents to come back, Elizabeth and Henry discover that dangers might already have entered the building. 

Trapped in a ruined city, Elizabeth and her brother, Henry, try to avoid the dangers that seem to lurk on every street. But even when they manage to get home, they face an entirely different kind of threat. Meanwhile, hundreds of miles away, Thomas struggles to keep his brother alive. First, though, he needs to find out what happened to his father, and he also has to make a difficult decision about his ailing mother.

Days 9 to 16 is the third title in the Mass Extinction Event series, continuing the story of a worldwide apocalypse seen from the eyes of two very different people in two different parts of the US. Finally realising that she must leave the city, Elizabeth sets out alone along a deserted road. Eventually, however, she encounters some fellow survivors, and before long she's taken to a remote farmhouse where a small community is struggling to take shape. She soon discovers, however, that this particular farmhouse hides some dark secrets.

Days 46 to 53 is the fourth book in the Mass Extinction Event series, continuing the story of a worldwide apocalypse seen from the eyes of two very different people in two very different parts of the US. More than a month after the disaster that crippled the world, Elizabeth and Toad are struggling to survive. Soon, however, Elizabeth faces a fresh problem, as she realises that the virus might have claimed another, even younger victim. Meanwhile, Thomas discovers more survivors who are trying to reclaim the city. 

Having been rescued from the forest, Elizabeth is shocked to find herself living with a small group of survivors. But when she's plunged into an unlikely reunion, she begins to realise that the task of saving humanity might require difficult decisions. Meanwhile, Thomas discovers the truth about another group of survivors. Old alliances are destroyed and new alliances are formed, but finally Thomas is forced to make a stand. 

One hundred days after humanity was brought to its knees, Elizabeth Marter has joined a small group of survivors in Boston. Under constant attack from scavengers who live beyond the city limits, Elizabeth and the others desperately try to come up with a plan. But when they learn that a more organized enemy is on the way, they realize that they face a battle for what's left of their resources.

Having finally met for the first time, Elizabeth and Thomas soon find themselves in mortal danger as the Mass Extinction series continues. Having encountered a strange little girl they found at the side of the road, Elizabeth and Thomas follow her to a seemingly abandoned old hospital. They soon...

The battle for Boston is over, but there are still dangers lurking in the city. And as Elizabeth and Thomas arrive, they discover that old enemies are waiting to strike back. Desperate to find her father, Elizabeth sets out to see if anyone knows whether he survived the battle. She soon learns...