The Nightwatch Division was a paramilitary organization under the Ministry of Peace, set up during the Presidency of Morgan Clark in 2259.
Nightwatch was established to recruit normal citizens, including local police, and encouraged them to uncover and report on what were perceived to be "subversive" activities. Such subversion was deemed to include open criticism of Alliance policy or the Clark regime, interacting with aliens on anything more than a professional basis, or anything else Clark deemed to be a threat to his new order. The Nightwatch also had the power to make arrests without warrants, detain suspected subversives indefinitely, and spy on the population at will.
Nightwatch began by offering extra credits to various people to be their eyes and ears[1]. Because of this, Babylon 5 security officer Zack Allan decided to join Nightwatch. He was in it for the extra money, but soon became more and more disturbed over the course of events, and the escalation of Nightwatch's activities. Zack became increasingly worried about the erosion of civil liberties that was happening with Nightwatch around.
Nightwatch and the Ministry of Peace were very closely integrated and were for all practical purposes synonymous by the time the Ministry attempted to impose a political officer (Julie Massante) on the station. She attempted to compromise Sheridan by bedroom politics (walked in upon by a holographic projection of Ivanova), which failed. She later addressed the station's Nightwatch contingent and informed them that they were now part of the political office, hence Zack's concern over Due Process was moot.[2]
With events on Earth coming to a head, Captain Sheridan and the others knew that the Nightwatch was a threat that would have to be dealt with. When Clark issued the martial law orders, Nightwatch was ordered to take over station security. Sheridan found a loophole in the orders for Nightwatch to take over station security - they had been issued by a civilian office outside the normal chain of command and were therefore invalid.[3]
Knowing he finally had a way of dealing with Nightwatch, Sheridan approached Zack, who agreed to help the command staff take care of the Nightwatch threat. Zack went to his Nightwatch superiors and revealed that a ship was arriving with a number of Narn who would take over station security. Believing that they could catch Sheridan in the act, nearly all the Nightwatch personnel went to the airlock where this ship was supposed to be docking. When everyone was assembled in the docking area, Zack gave the orders that sealed the Nightwatch personnel in the room. Sheridan then arrested all of them for attempted mutiny and failure to respect the chain of command. Each Nightwatch operative was ordered to come out one at a time and surrender their weapons and equipment. Sheridan then revealed that the local Narn population was then going to take over Babylon 5 security; as he put it, hiding a lie within the truth.[3]
The Nightwatch presence on B5 ended after the station declared independence from the Earth Alliance. All the known Nightwatch personnel were sent back to Earth. A small covert team remained. They were able to take Delenn hostage briefly, but were all either killed or captured when the station's command staff rescued the Minbari hostages.[4] Though the Babylon 5 branch of the organization was shut down, the Nightwatch remained an active force throughout the Earth Alliance until Earth itself was liberated by the resistance.