Original air date: Friday, February 10, 1978<br /> <br />The Enterprise responds to a drifting Klingon battle cruiser discovered near disputed space along the Federation border. The vessel appears abandoned, heavily damaged, and running on minimal power  but scans reveal a single life sign aboard.<br />Kirk leads an away team and discovers the lone survivor is not Klingon, but a human calling himself<br /><br />Lord Bobby, an eighteenth-century aristocrat who claims to have been abducted and brought aboard the ship. Polite, articulate, and strangely at ease in the alien environment, Lord Bobby quickly ingratiates himself with the crew once he is brought aboard the Enterprise.<br />But something about him doesn’t add up.<br /><br />As McCoy and Xon investigate, they uncover signs that the Klingon crew did not abandon ship, but turned on one another in a violent internal conflict. Meanwhile, subtle changes begin to appear among the Enterprise crew. Minor disagreements escalate. Emotions intensify. Discipline begins to fray.<br /><br />Xon determines that Lord Bobby is not human, but a parasitic entity capable of assuming a humanoid form while amplifying emotional instability in those around him. The destruction of the Klingon crew was not random, it was the result of tensions pushed to the breaking point.<br />As the situation escalates aboard the Enterprise, Kirk confronts the entity, which insists it does not create conflict, only reveals what already exists beneath the surface.<br /><br />With the ship’s stability at risk, Kirk and Xon devise a containment strategy that isolates the entity from further interaction. After a tense pursuit through the ship, Lord Bobby is captured and secured for transport to a Federation research facility.<br /><br />As the Enterprise departs, the crew is left to consider an unsettling possibility: that the most dangerous threats are not those imposed from the outside, but those already present, waiting to be exposed.