This is one of those weird episodes that doesn't seem to do a lot on the surface, being a monster of the week, but does actually fill in some of the backstory that will be needed later. It also tops up the mysticism.
The episode opens with Commander Sinclair at dinner, being interrupted by Delenn who wants to know why he isn't also on his way to greet a visiting dignitary. Sinclair is flustered by the lack of warning, as he wasn't told anyone was visiting, but he and Garibaldi put on their dress uniforms and join her. The visitor turns out to be Aldous Gajic, the last surviving member of an order dedicated to seeking the Holy Grail. He's run out of places to look on Earth, so is asking the ambassadors of the various alien worlds for assistance.
Garibaldi is not impressed with dressing up for this, and Sinclair takes it in his stride although is less than enthusiastic. The encounter works wonderfully to highlight the differences between human and Minbari thinking. Where Aldous would be ridiculed on Earth, the Minbari honour him. The Minbari revere what they call True Seekers for their dedication, even if the cause of it is only a myth.
The other plotline deals with someone else dedicated to a cause, although a very different one. Former construction worker Jinxo is being threatened by Deuce, an underworld thug he owes money, who wants repayment in credits or information. Since he can't afford the former and refuses the latter Deuce shows him what appears to be Ambassador Kosh sucking out someone's mind.
The safest thing to do would be to run, but he can't. As soon as Jinxo leaves Babylon 5 it will be destroyed.
During a bodged attempt to steal credits, Jinxo is arrested and remitted to the custody of his victim - Aldous Gajic - who was intrigued by Jinxo's courtroom plea not to be evicted from the station. It turns out he worked on the construction of all of the Babylon stations. The first two were sabotaged and destroyed while he was on leave. The third exploded sometime after he left, earning him the nickname Jinxo, and as he was leaving Babylon 4 "the station sort of wrinkled. Twisted like putty, then just disappeared." Jinxo thinks he's cursed; Aldous thinks he's lucky for getting out each time, and brave for risking his life to stop Babylon 5 suffering the same fate.
In the meantime, Doctor Franklin's been analysing the lurker who had their mind wiped. He works out the creature Deuce is keeping in a fake Vorlon encounter suit is a Na'ka'leen Feeder, which comes from a quarantined planet under Centauri jurisdiction. Deuce has smuggled one on board, and is using it to dispose of his enemies. Sinclair approaches Ambassador Mollari for information which he's happy to give - from the safety of his quarters.
Aldous takes Jinxo with him on his appointments to meet the ambassadors. Delenn is sorry to give Aldous the news that the Minbari have no record of the Grail, but promises that any news of it will be relayed to him. She doesn't specify how he'll be found, or why the Minbari have such a wide reach, and it's the first hint we get of the Rangers who will appear in Season 2. Jinxo is surprised at her helpfulness, given the relatively recent war between Human and Minbari. She tells him that the two castes of Minbari, Warrior and Religious, rarely agree and so they simply won't tell the Warrior caste to avoid confusing them. It later becomes apparent there are actually three castes, and it's not clear why the Worker caste was left out here.
The Centauri response is very different. Ambassador Mollari is irritated at being interrupted in shouting some harried administrator into reinstating the quarantine around the Na'ka'leen Feeder's home planet, and even more irritated when he alludes to fees for the time and difficulty in searching the records, only to find his aide Vir has already done it. It's a sharp contrast to his response to Sinclair's request for information, and a reminder of Mollari's self-interest. Next stop in the Vorlon ambassador, and when Jinxo sees Kosh in his encounter suit, he flees. Aldous follows him, only to be kidnapped by Deuce's thugs, in an effort to blackmail Jinxo into giving Deuce the construction information he wants.
Instead, Jinxo goes to Commander Sinclair. They arrive with a security team just in time to see Aldous sacrifice himself to save Deuce's other victim, Ombuds Wellington, the judge who was due to try Deuce. His dying lament is that he's failed in his quest, but Jinxo promises to carry on. With Sinclair as witness, Aldous names Jinxo his heir before he dies.
The episode comes full circle as Sinclair and Delenn meet at the docking bay to see Aldous depart. The coffin is escorted by Garibaldi's security team, and we see his change of opinion towards Aldous in his attitude towards the coffin - "Treat it gently, boys." His opinion of Jinxo hasn't changed, though, and when Sinclair wonders at Jinxo's absence he replies "Jinxo's not the type to keep promises". However Jinxo arrives dressed in the robes of his order, having decided to keep seeking the Grail. He reclaims his true name, Thomas, and Delenn hands him a crystal with the instruction to crush it on the ground where Aldous is buried: "It will glow each night for 100 years. It is our way with all true seekers."
There isn't much in the way of main plot arc here, only breadcrumbs, and the only new information is Jinxo's potted history of the first four Babylon stations. As with many of the monster of the week episodes, this one could be taken out without leaving much of a hole. However it does at least tie in with some of the show's main themes in how it looks at the nature of faith, and how the different races perceive things, which is more than some of the other standalone episodes do. It also ties together its two plots, with Jinxo as the lynchpin, in a way that makes sense. In that respect it's a successful episode, even if it's not one that's essential to watch.