An apocalyptic virus. A stolen cure. A life-or-death decision.

Two weeks after the mysterious "Scratch 'n Sniff" outbreak began in Boston, the world has descended into darkness.

Nick Ritter, an expert crisis consultant, shelters with his newfound family at a camp near the Canadian border. A harsh winter is coming, and time is running out to reach his survival ranch in New Zealand.

But Nick holds the key to stopping the pandemic: a stolen vial of Dr. Teddy Monroe's vaccine. Now the group faces a life-or-death decision: save themselves or save the world.

As the deadly virus and frigid winter close in, the family grapples with their new world:

• Abby Blackwell, a postpartum teen mother, reels from the arrival of her newborn twins, Max and Lily. When they bring an unexpected surprise, Abby considers the unthinkable: returning her babies to Dr. Monroe.
• Brian Donahue, a reawakened warrior, and his wife and daughter, Tracy and Zoe, thrive from their fresh start. But a powerful ally forces them to choose: a lonely future or a haunted past.
• Dana Foster, a battle-scarred doctor, accepts the broken world and opens her heart to Nick. But when she uncovers a dark secret, she questions if Nick is really the man she hoped.
• T.J. Chandra, a humbled startup CEO, worries the monstrous Kurt Hunziker will return for a violent revenge. An old friend offers T.J. a choice: the easy life or the good life.
• Herman and Mikey Reed, grandfather and grandson handymen, settle into the family they so desperately needed. Until a surprise arrival unleashes the harsh world they hoped to leave behind.

Now Nick must call on his disaster-planning skills to survive, facing off against the enraged Dr. Monroe, who will stop at nothing to reclaim his newborn twins. As Nick unravels Monroe's plan, he awakens something bigger and more sinister than he ever imagined.