A landing party on a lush planet begins to hallucinate.
Enterprise finds an Earth-like planet and sends an away team, including T'Pol, Tucker, Mayweather and Cutler, to camp overnight. A violent storm forces them to shelter in a cave, where pollen from the local plants triggers paranoia and hallucinations in the humans.
T'Pol, who is less affected, tries to keep the group calm while Tucker grows convinced that she and invisible creatures are plotting against them. Archer and Phlox work on an antidote as the storm prevents transport, and Archer resorts to the ship's still-unproven transporter to bring an injured crewman back. The episode was directed by David Livingston, with a teleplay by Mike Sussman and Phyllis Strong.