Voyager finds a probe that caused a disaster.
In its first official assignment from Starfleet since regular contact was restored, Voyager is asked to find Friendship 1, a 21st-century Earth probe sent out to share human knowledge with other civilizations. The trail leads to a planet suffering a nuclear winter, and an away team including Paris, Neelix and Lieutenant Joe Carey is captured by survivors who blame humans for their world's ruin.
The probe's antimatter technology had been misused, and an accident with it devastated the planet. The hardline leader Verin kills Carey during a hostage exchange, but the scientist Otrin works with Voyager, and the crew frees the remaining hostages. Voyager then uses nanoprobes to restore the planet's atmosphere, ending the long winter.