Hugh, formerly Third of Five, was a former Borg drone who was rescued by the USS Enterprise-D in 2368.
Hugh was found in the Argolis Cluster at the crash site of a Borg scout ship.
Hugh himself was critically injured. He was brought back to the Enterprise-D for medical attention by Dr. Beverly Crusher under protest from Captain Picard. Upon arriving on the Enterprise-D, Hugh was placed in the brig and kept under guard at all times. He had trouble adapting to his new environment, having been cut off from the resources of the Collective for the first time in his life. Where there had been millions of voices in his head, there was now only his own. Dr. Crusher eventually nursed him back to health, and chief engineer Geordi La Forge found a way to nourish the drone similar to the regeneration alcoves on a Borg ship.
Captain Picard saw this as an opportunity to destroy the Borg once and for all. He ordered La Forge and Lieutenant Commander Data to devise a method to destroy the Collective through an implanted program or file in Hugh, much as Data had done to a Borg cube through Captain Picard (as Locutus) two years earlier. Dr. Crusher did not agree with this course of action, because they were talking about exterminating an entire race – even if it was the Borg.
As Hugh spent more time with the Enterprise-D crew, he learned many things. La Forge taught him that Humans did not want to be assimilated into the Collective, which contradicted what Hugh had been taught by the Collective. La Forge gave Hugh his name, through a mispronunciation of the word "you", and became Hugh's first ever friend. Guinan, who originally wanted nothing to do with Hugh, taught him that resistance is not futile. Guinan's homeworld had been destroyed long ago by the Borg, but the fact that Guinan was still alive was proof of her lessons to Hugh.
Picard eventually confronted Hugh. Hugh immediately recognized Picard as Locutus, and Picard took the role of Locutus while talking to Hugh, to simulate the authority that Hugh was used to. However, La Forge, Guinan, Data, Dr. Crusher, and other members of the Enterprise-D crew had produced a profound effect on Hugh. When Picard reminded him that resistance is futile, Hugh replied that resistance was not futile. When Picard told Hugh that La Forge will be assimilated, Hugh stated that La Forge did not wish to be assimilated. When Picard said that this was irrelevant, Hugh specifically said that he (and Hugh used the word I; his second use of a singular pronoun) would not assist in the assimilation of La Forge. Picard was stunned that a Borg drone would say such things.
Picard decided that he could not send Hugh back with the file that would destroy the Borg. He offered Hugh asylum on board the Enterprise-D, but Hugh said that the Collective would not stop looking for him until they found him. Hugh agreed to go back to the crash site, and to be taken back into the Collective, to protect the Enterprise-D from harm.
Hugh's new found sense of individuality proved to be almost as deadly to the Collective as any file stored in his memory could be. His experiences on board the Enterprise-D were spread to other drones, and eventually Hugh's cube fell into a complete state of disarray. The Borg's sense of shared identity had been disrupted, and they were no longer able to function. The Collective disconnected Hugh's ship from the hive mind and left the cube drifting in space until 2370 where it was discovered by Lore, Data's brother. Lore took advantage of the confused drones and assumed leadership of the group. He brought order to chaos, and allowed the drones to maintain their individuality but was able to control them. Lore "promised" to create the Borg crew in his image, running tests on various drones, leaving them with awful injuries.
Hugh disapproved of Lore's leadership, finally realizing that Lore had no clue how to keep his promise to the drone crew, and while Lore had acquired a ship and had built a base on a remote planet, Hugh took a group of drones underground and became a leader himself. Hugh and the drones loyal to him assisted the Enterprise-D crew in rescuing Picard, La Forge, and Troi and recapturing Data from Lore.