The 100 season 4 will be about survival, as the theme this season will be about Earth striking back. The Sky Crew have survived the Mount Weather in season 2, Alie in season 3, but this new threat to humanity aka a second Nuclear Apocalypse is threatening to wipe out everything they hold dear.

The CW also released a Comic-Con trailer at the event, featuring a recap of what happened in season 3 and hinting at the new threat awaiting The 100 team in season 4. Clarke poses an important question in the video, as she asks, "When all is lost, can hope survive, can we survive? And after everything we have done, do we deserve to? The trailer ends with an ominous shot of a black cloud of smoke and lighting taking over Polis.

The 100's executive producer Jason Rothenberg attended the San Diego Comic-Con 2016, and teased a grim fate for humanity ahead. Rothenberg explained that the black clouds in the trailer are a hint about what is to come. "[Though it] probably wouldn't be until the end of the season. ... The earth strikes back in Season 4. ... It's an unbeatable foe. It becomes not how to stop it; it becomes, 'How do we survive?' There aren't enough life boats. ... It's a return in a lot of ways, thematically, to what we did in Season 1. ... The earth is the Ark," he said.

Eliza Taylor, who plays Clarke Griffin, teased, "It's going to be interesting to watch a group of people, humans, trying to survive. This is an enemy we can't defeat, so how do we move forward? In true Clarke fashion, that will be trying to get everyone on board."

Marie Avgeropoulos, whose character Octavia was last seen mercilessly killing Pike in the season 3 finale, is headed for a "really dark turn". Avgeropoulos said, "Yes, it's possible to go darker. ... She's going to go ahead and do what she does best, which is killing people." The fourth season will also address Octavia's fractured relationship with brother, Bellamy.

The 100 season 4 will return in January, 2017.