Nightmares herald the presence of an alien race who've mastered the dream state. Chakotay's experience in lucid dreaming seems Voyager's best hope of escaping a shared dream entrapment.
The Voyager crew are assaulted in the form of nightmares. An alien species, functioning only in a dream world, disables the crew and traps them in a shared dream. Chakotay strives to stay awake and help The Doctor disable the aliens' hold on the crew, all while wondering if he is still dreaming.—Meribor