Overview: A member of the dangerous cybernetic race known as the Borg is captured by the Enterprise crew and examined. During the course of the interactions which follow, they begin to rethink their attitude towards the Borg.
The Enterprise discovers a wrecked Borg scout ship with a single survivor amongst the wreckage: a young Borg drone. Dr. Crusher insists on treating the surviving Borg, and Captain Picard reluctantly agrees to transport him aboard the Enterprise.
Given that the Federation is technically at war with the Borg (despite an absence of official declaration on their part), the crew are initially wary of the rescued Borg, which eventually is given the name Hugh. The idea of using the drone as a weapon of mass destruction is one of the central themes of the episode, with Picard and the crew considering sending back Hugh to destroy and/or cripple the Borg. This idea is refined throughout the show, eventually culminating in the planned use of a paradoxical mathematical construct which would be inserted into the Borg drone's memory banks and would be passed to the central collective due to the drone's inability to process it, causing chaos at the heart of the Borg collective. The morality of such an action is called into question by Dr. Crusher who maintains that genocide should not be a consideration. Picard counters by saying that with any other race the idea would be out of the question, but the nature of the Borg calls for extreme measures. The Borg drone (played by Jonathan del Arco), calling himself "Third of Five" (per his position aboard the five-crew scout ship), was dubbed "Hugh" by Geordi La Forge following a conversation of self and Human "designations." Hugh explains that the Borg only wish to learn about other cultures and cannot understand why Geordi does not want to be assimilated. The engineer begins to explain individuality, and leads onto friendship. In the course of working with Hugh, Geordi begins to question the action of genocide as Dr. Crusher does. These questions are compounded when Hugh begins to display traits of individuality. This demonstrated independence raises another question of morality for the crew: Is it right to sacrifice one individual to protect the majority?
Geordi voices his concerns to Picard who dismisses them with little thought, suggesting that the engineer "un-attach" himself from the drone. Geordi then speaks to Guinan whose homeworld was destroyed by the Borg. Despite initial skepticism and displayed repugnance at the idea of giving a drone a name, Guinan goes to meet Hugh. Her skepticism is called into question when she does not find the expected mindless drone, but a confused young individual who concedes that "resistance is not futile," at clear odds with the mentality of his people. Now with her own doubts, Guinan speaks to Picard and urges him to meet with the Borg. He does so under duress, pretending at first to be Locutus of Borg in front of Hugh, and ordering him to assimilate the crew of the Enterprise, including Geordi. Hugh resists the idea, claiming that Geordi is his friend. When Picard pushes him further, he states "I will not assist you," shocking Picard with his use of the first person singular, and prompting the captain to reconsider his plans.
Picard concludes that it would be immoral to use Hugh as a weapon to destroy his people, and offers the drone asylum within the Federation. Hugh is tempted but realises that the Borg, having lost a drone, would continue to look for him, placing the Enterprise and her crew in jeopardy. He decides to go back to the crash site and be re-assimilated by the Collective - a plan which Picard theorises may cause disruption of its own, with Hugh's individualism spreading throughout the Collective.
As the Enterprise masks itself from the recovery ship's sensors, Geordi accompanies Hugh to the crash site and witnesses him being "rescued" and reassimilated. Just before Hugh is transported aboard the Borg vessel, however, he gives a small parting glance to Geordi.