Chief Engineer Trip Tucker is off-ship testing the new autopilot technology on one of the Enterprise's shuttle pods — using a nearby gas giant planet and its numerous moons as a convenient gravitation-heavy obstacle course. Without warning, his craft is suddenly approached and fired upon by a small shuttle-sized and unknown ship. With the main shuttle systems damaged and central power lost, he is soon forced to crashland on one of the planet's many moons.
Meanwhile, having lost contact with the shuttle, the Enterprise commences a search of the area. They are soon intercepted by a large ship belonging to Arkonians, who claim this region as their own. The Arkonians are territorial, aggressive, and have their own strained history with the Vulcans. While they demand that Enterprise immediately set course out of their system, their captain is reluctantly persuaded by Captain Archer to agree to a combined search of the sixty-two moons - it seems the aliens have lost one of their shuttle pods as well.
On the planet, Tucker survives the crash relatively unscathed, and builds a fire in order to keep warm. He also tries to repair the communications systems, and he soon realizes that he is not alone, however, and is ambushed by his attacker, who has also crashed on the moon. Having had his communications panel stolen, Tucker is forced to track down the alien and his ship, but is captured in the ensuring fight. He is soon able to turn the tables however, briefly taking the Arkonian pilot hostage, but they both are exhausted in the ensuing fist-fight. Finally a truce of sorts occurs as they both realize that surviving is their main goal.
Finally, Tucker is able to use the surviving technology from both shuttles to get the transmitter working, and he successfully contacts the Enterprise. To complicate matters, the sun is now slowly rising, and the temperature on the moon is becoming lethally hot. Moreover, since the moon's atmosphere interferes with the shuttle pods' power systems, the Enterprise will have to beam the survivors up. But the alien, being unable to sweat, is in too much physiological distress to survive the trip, and Tucker won't abandon his new friend. Archer then has the Arkonians launch a shuttle modified to function in the moon's atmosphere. Later, with the crew back on board, Sub-commander T'Pol concedes that the rescue has allowed for friendlier and more productive relations with the Arkonians in one day than the Vulcans managed over a hundred years.