When we last left The 100, the evil A.I. known as A.L.I.E. failed to entice the survivors into the City of Light, but before Clarke took care of her, A.L.I.E. revealed that the nuclear power plants that remained were melting down, and that 90% of the Earth’s surface will be uninhabitable within 6 months. Obviously this means that things are about to get really nasty for the grounders and everyone else. This trailer does a great job of showing us how bad things are going to get. Downright gruesome. I have no idea how our heroes are going to survive this season, but I can’t wait to find out.