In the Earth year 2257, a multitude of humans and non-humans gather deep in neutral space at a new station,
Babylon 5, which has recently become operational.
Babylon 5 was built as a neutral venue for discussing and resolving issues between the five major spacefaring races of the galaxy, the
humans,
Narn,
Centauri,
Minbari, and
Vorlons. Commander
Jeffrey Sinclair is in overall charge of the station. As the crew awaits the arrival of the fourth and final alien ambassador, Ambassador
Kosh from the Vorlon Empire, a transport ship arrives from Earth, bearing
Lyta Alexander, a human telepath who joins the station crew, and Del Varner, a civilian. Ambassador Kosh arrives two days ahead of schedule, and is on board the station less than a minute when he suddenly falls ill, apparently from poisoning.
Babylon 5 chief medical officer,
Dr. Kyle, conducts a medical investigation and seeks to prevent Kosh's death, while Security Chief
Michael Garibaldi conducts a security investigation. Worried that, if Kosh dies, the Vorlons will attack and destroy the station, Dr. Kyle and
Lt. Cmdr. Takashima persuade Lyta to perform an unauthorized mind scan on the unconscious Kosh. As she conducts the scan, Lyta sees Commander Sinclair poisoning the Ambassador. Lyta accuses Sinclair of attempted murder. A meeting of
Babylon 5s Council, made up of delegates from all five races, resolves to extradite the Commander to the Vorlon homeworld for trial. Sinclair is told that he will be deported in twelve hours. Garibaldi comes to suspect Del Varner might have been involved in Kosh's poisoning. When he enters Varner's quarters, however, he discovers Varner dead in a fish tank. Lyta enters the medical lab, where she begins adjusting some of the settings that are keeping Kosh alive; when Dr. Kyle realizes what she's doing, he tries to stop her, and she attacks him. At that moment, the real Lyta Alexander enters the room; her double escapes. Upon further investigation in Varner's quarters, Garibaldi learns that Varner had been smuggling illegal items between systems, and that he most recently had gone to the Antares sector to acquire a changeling net: a device that can make an individual appear to look like somebody else. The crew realizes that Kosh had not been poisoned by Sinclair when he arrived at the station, but by someone using the changeling net to imitate Sinclair. Since the use of such a device would put out a lot of energy, Takashima uses the station's scanners to pinpoint an area of the station with a high concentration of unidentified energy use. Sinclair and Garibaldi head for that part of the station, just as a Vorlon squadron arrives in the vicinity of the station to pick up Sinclair for his voyage to the Vorlon homeworld. Sinclair and Garibaldi confront the mysterious assailant. Garibaldi is injured in the firefight and Sinclair faces the assassin himself. The changeling net is disabled, revealing the assailant to be a Minbari assassin. The assassin is a member of the Minbari warrior caste and wanted to discredit Sinclair as retribution for Sinclair's role in the
Earth–Minbari War ten years earlier. Sinclair asks the assassin why he did it; the assassin replies simply, "There is a hole in your mind." Sinclair, being informed that the assassin has triggered an explosive charge, manages to get away just before an explosion rips a hole in the station's hull, throwing the station off its axis and beginning to tear it apart from the inside. Takashima uses the station's stabilizers to reestablish its axis. The Vorlon delegation, now satisfied that Sinclair is innocent, drops all charges against him. In the station's garden, Sinclair reveals to
Delenn what the Minbari assassin had said about the "hole" in Sinclair's mind. Delenn claims that it is just an old Minbari insult. Sinclair, however, tells her that he had fought in the climactic battle of the Earth–Minbari War, and that there is a twenty-four-hour period in the climactic battle, just before the Minbari surrendered, which he can't account for. Takashima declares Babylon 5 open and operational. == Cast ==