On Centauri Prime, in the future, Londo Mollari (Peter Jurasik) tells John Sheridan (Bruce Boxleitner) that it has been 17 years since the Shadow War. He is dying, but he sends Sheridan to prison to await his execution. Back in 2254, Babylon Four is damaged by the electromagnetic pulse caused by the Shadows’ fusion bomb. Ivanova (Claudia Christian) explains to Marcus Cole (Jason Carter) that they need to locate an access panel. They are trying to steal Babylon Four and take it away in Time. Two members of Babylon Four security confront her. She hears Cole’s Minbari fighting pike opening, jumps on one of the security guards, and he drops onto the other.
In 2278, Sheridan, in a Centauri prison-cell, goes time-travelling again. In 2254, Zathras (Tim Choate) sees Sheridan fade in and out. Sinclair (Michael O’Hare) and Delenn (Mira Furlan) are blocked by engineers. Ivanova creates a diversion with the access panel. In 2278, the future Delenn is put into the cell with Sheridan and tells him they have a son. In 2254, Ivanova creates a fake hull breach alert, and pressure doors block access of the Babylon Four crew. In 2278, Sheridan tells Delenn he is from the past. The guards come for them.
They are brought to the throne room, where Emperor Mollari is drunk. Attached to him is a tentacled creature called the Keeper, placed there by his Shadow masters. The creature can’t hold its liquor and Londo can only act on his own when he is plastered. He sends Sheridan and Delenn to an escape ship. Afterwards, an old, eye patched G’Kar (Andreas Katsulas) arrives. Londo begs him to kill him. He begins to strangle Londo, but the Keeper wakes up and makes him strangle G’Kar. Almost free, Sheridan finds himself travelling in time. Delenn tells him not to go to Z’ha’dum. Back in the throne-room, Vir (Stephen Furst) enters, finds Londo and G’Kar dead, and picks up the Emperor’s badge of office.
In 2254, a spacesuit near Zathras begins to fill up with Sheridan. Sinclair comes in wearing an identical suit. In the suits, they take the last components of the time-system to Babylon Four’s power core. Something goes wrong and the whole station becomes unstable in Time. On the White Star, Zathras gets it back under control, but Sheridan disappears. Delenn has a vision. Sinclair appears, much older, a result of the time-travel. Ships are coming, but Sinclair knows it is the crew from Babylon Five investigating.
Babylon Four Security takes Zathras away. Zathras meets past Sinclair and remembers not to recognize him. Not the One. Events from the past of Babylon Five take place, but from the point of view of Babylon Four. The suit comes back to save Zathros, but Delenn is in it. Everyone takes to the White Star, except that Sinclair stays to pilot Babylon Four into the distant past. Sheridan takes the White Star, sadly, to the Babylon Five present. Delenn points out that human and Minbari souls began crossing a thousand years ago. Babylon Four is way back in 1260 now. Sinclair enters a chrysalis. Vorlon and Minbari ships arrive and Zathras leads them to Sinclair, who has become the Minbari cultural founder Valen—a Minbari not born of Minbari.
The spacesuit was one made for but never used in 2001: A Space Odyssey. The episode was cobbled together because Michael O’Hare was seriously ill and leaving, which made it all somewhat confusing. Much of it was looking back at an earlier episode called Time Squared in which Babylon Four popped in and out of time with the crew of Babylon Five along for the ride. The parts didn’t always fit, but it’s surprising how well it was done. There were several time paradoxes—the sort of thing that delights us in time-travel stories but can also give us a serious headache. Zathras is a lovable character and shines in this. As always, though, Londo, G’Kar, and Vir are wonderful to see. Having planned out the series to the end, J. Michael Straczynski was forced to take the end and move it into the middle, then re-write the rest of the series.