At Dr. Phlox's request, Enterprise attempts to retrieve 3 Denobulan scientists from the planet Xantoras, where the Goverment has ordered all off-worlders to evacuate within 3 days. Tucker, Reed, and Mayweather navigate a series of labyrinthine underground caves in search of the scientists. Meanwhile, Enterprise lends assistance to a damaged ship fleeing the planet. Doctor Phlox faces an ethical dilemma when one of the refugees of the ship refuses life-saving treatment. The patient, an Antaran, holds a grudge against Phlox stemming from a war between their races that ended 300 years ago and would rather die than be treated by a Denobulan. Phlox defies Archer's direct order to force treatment because it goes against the Deobulan code to yield to "the will of the patient."