Just when we think the worst is behind us, "The 100" likes to throw a new apocalyptic curve ball our way. By the end of Season 3, it seemed like Clarke (Eliza Taylor) had saved everyone from the evil artificial intelligence program that's been warping their minds, only to find out that an even bigger threat has been lurking in the background all along.

According to ALIE, nuclear reactors have started to break down all over the planet, meaning the Earth is facing yet another nuclear radiation crisis.

The Sky People might be immune to the small amounts of radiation still left on the ground, but not even they can withstand the fallout from a nuclear power plant explosion.

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Zap2it caught up with the cast of "The 100" to ask how our favorite delinquents will be managing this new problem.

According to Eliza Taylor (Clarke), the answer could lie in returning to space or in going underground. However, Chris Larkin (Monty) makes a good point about that first option. "They already tried space, and it didn't work. You're always going to have to come back to the ground," Larkin says.

Henry Ian Cusick, who plays formerly corrupt (and now downright cuddly) Marcus Kane, is more concerned with the lack of leadership on all sides of the board after the mess with ALIE last season.

"There's power vacuums in Polis, we need a leader there. We need a leader with our group as well," says Cusick.

After Lexa's (Alycia Debnam-Carey) death and the slaughter of the nightbloods, Polis will be looking for a new Heda, which will probably take priority over any nuclear problem the Sky People warn them about.

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Arkadia is facing a similar crisis. No matter how terrible he was, Pike (Michael Beach) was the elected chancellor, and now he's dead. So how takes up the mantle now?

Whoever these new leaders are, let's hope they get with the program fast. Our characters only have six months to live, and no time to waste!

"The 100" is set to return in the spring of 2017.

Posted by:Lindsay MacDonald

Lindsay MacDonald is a Los Angeles based entertainment reporter with an affinity for CW superheroes. She graduated from Pepperdine University with a major in Media Studies and a borderline unhealthy obsession with TV in 2012. She would much rather spend the day binge-watching ‘The Flash’ or sorting ‘Game of Thrones’ characters into Hogwarts houses than venturing outdoors. TV words to live by: “Never ignore coincidence. Unless, of course, you’re busy. In which case, always ignore coincidence.”