"Invasive Procedures" is the 24th episode of the American syndicated science fiction television series Star Trek: Deep Space Nine. It is the fourth episode of the second season. Set in the 24th century, the series follows the adventures on Deep Space Nine, a space station located near a stable wormhole between the Alpha and Gamma quadrants of the Milky Way Galaxy, near the planet Bajor. This episode explores the Trill species, of which DS9 officer Jadzia Dax is a member: They are formed of a host and a symbiont, with the symbiont passed from host to host as the previous one dies. In this episode, a bitter unjoined Trill attempts to steal the Dax symbiont from Jadzia. Plot During a plasma storm, Deep Space Nine is evacuated, with only a skeleton crew remaining behind to maintain the station until the event passes. Posing as a cargo transport in distress, an unjoined Trill, a pair of hired Klingon mercenaries, and a former prostitute named Mareel board the station and overpower the crew. Major Kira tries to take Mareel by surprise, but Mareel outfights her. The Trill, Verad, once applied to be joined with a symbiont and was rejected; now he wants the Dax symbiont. After restraining the shapeshifting Constable Odo in a container and taking the rest of the crew hostage, he forces Dr. Bashir to transfer the symbiont into his body. Without her symbiont, Jadzia will die within hours. Bashir has one of the Klingons assist him as he tries to save Jadzia's life. Meanwhile, Commander Sisko deals with Verad, who now has the memories of all the Dax hosts, including Curzon Dax, who was a very close friend and mentor to Sisko. He implores Verad to set things right, but sees that he intends to let Jadzia die. Meanwhile, Mareel, whom Verad had befriended early in life, begins to realize how much the man has changed since he received the symbiont, and begins to think the joining may have been a bad idea. However, she remains loyal to him. The bartender Quark, who helped Verad and his crew board the station by bypassing the security lockdown, pretends to be injured and thereby provides Bashir with the opportunity to sedate one of the Klingons. He then cracks the lock on the container holding Odo. Once Verad discovers what has happened, he heads for his ship, taking Kira as a hostage.