While traveling in a shuttle to the planet Ledos for a conference on Warp Field Dynamics, Chakotay and Seven of Nine take a small detour to admire the natural landscape. There they scrape an ancient energy barrier that begins to break the shuttle apart. Chakotay manages to blast a temporary hole through the barrier. The shuttle falls through but still threatens to break apart. Moments before it explodes, the two beam to the surface.
They find themselves in a lush jungle. In spite of Chakotay's leg injury, they decide to search for the shuttle's debris in hopes of constructing a distress beacon.
While searching, they encounter a tribe of primitive humanoids called the Ventu living in the jungle. Because of the Prime Directive, Chakotay and Seven agree to limit their contact with the Ventu as much as possible.
While in contact with the Ledos authorities, Paris performs an illegal flying maneuver within Ledos space. Despite his years of training as a pilot, the Ledos authorities insist he undergo a one-on-one piloting class as punishment. Janeway agrees to this, partly as a way to maintain good relations.
Seven is forced to go it alone as Chakotay is too injured to continue. Seven herself becomes lost and loses her tricorder down a small but deep hole.
As Chakotay rests from his injury, he is found by two Ventu and taken to their camp, where they begin healing his injuries. He begins to communicate with them and becomes impressed with their hospitality and culture. Out of necessity, Seven must affect their culture also, in order to watch out for Chakotay. The primitives come to emulate the two, even copying Chakotay's facial tattoos. One copies Seven's implants with debris taken from the shuttle.
Chakotay and Seven eventually disable the ancient energy barrier, mainly using the front section of the shuttlecraft. Voyager learns the barrier was erected by an alien species to separate the peoples of Ledos, protecting the Ventu from invasion and colonization. These aliens were eventually assimilated by the Borg (which is how Seven was able to penetrate the field during the crash). The shield going down opens up the primitive inhabitants to outsiders. The Ledos authorities promise Voyager the Ventu would be free of corruption but they see this is not true. Paris, under the protests of his driving instructor, uses dramatic and skillful piloting to help reestablish the barrier, freeing the primitives from any more cultural contamination by the outside world.