A Haakonian ships contacts the crew of USS Voyager to say that they have Jetrel on board. Jetrel was a scientist who created the Metreon Cascade, a weapon of mass destruction. The weapon was used on Rinax where it kills untold numbers of Talaxian including the family of the chef Neelix. Jetrel wants to come aboard as he believes Neelix is infected with a virus. Despite Neelix's protestations, Captain Kathryn Janeway allows Jetrel to come onboard.
Jetrel wants to test Neelix for a virus but refuses to initially before eventually agreeing. Jetrel tells Neelix he is suffering from Metremia, a disease and that the cure lies on Rinax.
Janeway takes Voyager to Rinax where Jetrel shows his colours, he tries to take control of Voyager. He wants to try to bring back the dead which he thinks he can do. The plan doesn't work out and Jetrel dies.