Ninety-seven years in the past, nuclear Armageddon decimated planet Earth, destroying civilization. The one survivors have been the 400 inhabitants of 12 worldwide area stations that have been in orbit on the time. Three generations have been born in area, the survivors now quantity four,000, and assets are operating out on their dying "Ark." Among the many 100 younger exiles are Clarke, the intense teenage daughter of the Ark's chief medical officer; the daredevil Finn ; the brother/sister duo of Bellamy and Octavia, whose unlawful sibling standing has all the time led them to flaunt the principles, the lighthearted Jasper and the resourceful Monty. Technologically blind to what's taking place on the planet beneath them, the Ark's leaders - Clarke's widowed mom, Abby ; Chancellor Jaha ; and his shadowy second in command, Kane - are confronted with troublesome choices about life, demise and the continued existence of the human race.