Watch: new 'The 100' Season 4 trailer.

Ahead of the premiere of Season 4 of 'The 100' next month, a new trailer has been released which hints at the forthcoming dilemma of radiation poisoning.

"For two seasons, the refugees of The 100 sent to Earth have been at war. First with themselves, then with the Grounders, and finally with Mount Weather. Many have lost their lives along the way. All have lost their innocence. They have learned the hard way that in the fight for survival, there are no heroes and no villains. There is only the living and the dead. But now the war is over. The battle against Mount Weather has been won. The prisoners have returned home to a world seemingly at peace, but can they find peace within themselves after what they had to do to escape? And is there more to life than just surviving? Unfortunately, their newfound sense of normalcy will be short-lived, and their lives will be changed forever, as threats both old and new test their loyalties, push them past their limits, and make them question what it truly means to be human. First, they fought to survive. Then, they fought for their friends. Now, they will fight for the human race."

Watch the new trailer below...