An attack by an intelligent energy source robs Tuvok of his mental prowess, leaving him exposed and vulnerable. He soon starts experiencing emotions he never expressed before. Janeway searches for the "shadow people" responsible for the attack. Neelix takes care of Tuvok the entire time. 

Voyager crosses paths with a graviton ellipse, a rare spatial anomaly that swallowed the Ares IV, an Earth ship orbiting Mars in 2032. The discovery calls for an away mission to search the 300-year-old U.S. spacecraft from the first manned mission to Mars trapped inside this massive ball of energy.