Captain Kirk and the U.S.S. EnterpriseTM join the Klingons to avert disaster in the Taygeta V system, where a time/space warp has swallowed a spaceship without a trace. Spock suspects a link between the anomaly and the inhabitants of Taygeta, semi-aquatic creatures killed for the jewel-like tears secreted at the moment of death. But a mutinous Klingon officer threatens the vital mission, as a desperate Kirk and Spock race to save the Taygetians, the Federation, and the entire universe.