Complex sentence: Humphreys works on fixing the heat generator at one of the cabins and catches an eco-terrorist, Doug Spinney, who tells the group that there's a deadly swarm of insects is in the forest and that they must avoid darkness to stay alive.
Split into simpler sentences: Humphreys works on fixing the generator at one of the cabins and catches one of the eco-terrorists, Doug Spinney. Spinney tells them that there's a swarm of something deadly in the forest and that they must avoid darkness in order to stay alive.