When the show begins, Dr. Bashir and Jadzia Dax are in the runabout on their way to rescue some folks in a ship that is falling apart. Once aboard, they find a woman, Ty Kajada, and a man, Rao Vantika. Rao is dead and Ty was apparently taking him to face justice when the ship was damaged. Oddly, Ty warns the two that although Rao appears dead, they should NOT assume this is true! In fact, when she later awakens in sick bay, Ty once again tells them that Rao MIGHT still somehow be alive. Apparently, Ty is some sort of evil scientist who has been trying to reach immortality. Despite Ty's many warnings, the crew miss the message. And, when it becomes apparent Rao IS somehow alive, they assume his evil essence is within Ty--even though SHE was warning them all along!
Despite the crew being dumber than a sack of doorknobs, this is still a decent episode. And, even with some overacting towards the end, the plot is just too interesting for the show not to work regardless. Not a shining moment...but worth seeing.