Ambassador Mollari realizes his deal with the Shadows has become dangerous and tries to sever ties with Mr. Morden, but fails. Kosh informs Sheridan that the Shadows can be fought with telepaths. The Vorlons attack the Shadows at Sheridan's insistence, but the Shadows kill Kosh in retaliation. Sheridan's wife, presumed dead on an archaeological dig on the planet Z'ha'dum years earlier, arrives at the station and convinces Sheridan to accompany her to Z'ha'dum. The Shadows attempt to force Sheridan to join their cause, their ships threatening "Babylon 5". Sheridan, guided by Kosh's words, flies a vessel loaded with explosives into the planet while jumping into a large chasm. The Shadow ships withdraw, but Garibaldi, deployed to defend the station, does not return. Sheridan returns from Z'ha'dum with the help of a strange being known as Lorien, who has given Sheridan 20 more years to live. The Vorlons alarm the other races when they begin destroying entire planets that have been influenced by the Shadows. Mollari, fearing the Vorlons will destroy Centauri Prime, destroys the Shadow base there and executes Mr. Morden. Sheridan learns that the Vorlons and Shadows were tasked as caretakers for younger races in the galaxy, but due to profound differences in ideology have been at war for eons, using the younger races as pawns in a proxy war. With the help of other ancient races, Sheridan convinces the Vorlons and Shadows to leave and cease interfering with the younger races. Garibaldi returns to "Babylon 5", with no explanation for his disappearance. He has unexplained changes in behavior and distances himself from the command staff, resigning and relocating to Mars to work with tycoon William Edgars. He also subdues Sheridan, allowing the latter to be kidnapped. It is revealed that Garibaldi was co-opted by the Psi-Corps to spy on Edgars, who is found to be developing a virus to destroy telepaths. With the Vorlons and Shadows gone, Earth's totalitarian government attempts to use the captured Sheridan as a propaganda tool, but Garibaldi - now free from Psi-Corps influence - rescues him. A brief civil war breaks out on Earth, culminating in President Clark's suicide and Sheridan's surrender to Earth forces. Ivanova is critically injured in the war, and leaves the station to take command of her own vessel.