This episode brings us back round to Earth politics, and we get Garibaldi's backstory, both neatly tied up in a bow. It's fairly straightforward with an episode's worth of A plot and no B plot, and most of what it achieves is setting up groundwork for the season finale.
The fraught nature of things back on Earth is mentioned in the opening shots of a news channel reporting on President Santiago's upcoming visit to the station, which many people think are to build support for trade and immigration agreements with the alien races. He's bringing with him an escort of Cobra fighters that will be permanently based on Babylon 5, and while inspecting the bay they'll be housed in Garibaldi and Ivanova narrowly miss being caught in an explosion that kills a man and injures another.
The chief of presidential security, Major Lianna Kemmer, takes over the investigation. Unfortunately she has a personal issue with Garibaldi, and after she sidelines him and takes over the investigation Garibaldi loses his temper at a petty thief he catches for the third time that month. Sinclair takes him aside and demands an explanation. "I need a drink," Garibaldi replies, and orders water, making it pretty obvious the way his explanation is going to head. Given their long history, it hard to believe Sinclair doesn't already know himself.
Seventeen years previously, Garibaldi had been the only clean cop in the Europa ice-mining operation. The stress of trying to uphold the law when no one else cared made him hit the bottle pretty hard. His only other comfort was the time spent with the family of his friend Frank Kemmer - the Major's father - and they kept him "sane and sober". Then Garibaldi's work started to pay off, and in retaliation his enemies rigged a shuttle pad to explode as Frank ended his run. Garibaldi was framed for negligence, blackballed, and hit the bottle again.
Kemmer decides to interrogate Nolan, the survivor of the accident, even though doing so will kill him. When his response is "bomb" and Garibaldi's name she's more than happy to assume Garibaldi is guilty of sabotage. She has his quarters searched and her second in command Cutter finds Centauri ducats and schematics of the Cobra bay, clear proof of Garibaldi's guilt. She's not prepared to look any deeper, especially with traces of explosives found in the bay. Sinclair accuses her of a personal vendetta, and Garibaldi goes on the run.
Sinclair tries to buy time to find Garibaldi first by cancelling Kemmer's station-wide alert, knowing it will take time for her to contact Earth to have him overruled. Ivanova assists by ordering maintenance on the communications channels that will tie them up for several hours. Kemmer gets round it by using the comms channel on her ship, but it's enough to give Garibaldi a headstart.
He goes to see Ambassador Mollari, a sensible place to start given the Centauri ducats but Londo knows nothing about the plot. He suggests the Narn are responsible, having extorted ducats from the Cetauri in exchange for the scientific data they took during the occupation of Ragesh 3 in the first episode. Londo loans Garibaldi some money to get him by, stating he feels some measure of sympathy - but if Garibaldi's caught, he'll deny speaking to him. The next stop is Ambassador G'Kar, who denies his people are involved and invites Garibaldi to defect. Both of these encounters serve mainly to add characterisation to the parties involved. Londo is, as always, a hopeless romantic in rooting for the underdog, G'Kar is sneakily political and pragmatic, and Garibaldi himself states he'd rather die than take up G'Kar's offer.
Garibaldi's next stop is to try the station's criminal underworld, where he's refused service and then attacked. Sinclair tracks him down and saves him from a beating, once again proving to be a hands-on sort of commander, and tries to persuade him to come in. Garibaldi refuses and escapes while Sinclair's distracted. He insists on finding out who framed him, but instead ends up in a bar at the bottom of a bottle.
Sinclair takes a call from General Netter ordering him to give Kemmer his full co-operation. He obeys, but accuses her again of having a personal vendetta. At this point they find out Garibaldi's been spending Londo's Centauri ducats, which only serves to make him look more guilty. Shortly after this he's brought in, drunk. Kemmer takes him to her command centre, while Cutter checks the bays again ahead of the president's arrival.
By this point in the season it's clear that Sinclair will try to get what he needs within the limitations set by his rank and the diplomatic demands of his position. In this case he gets Welch, Garibaldi's second, to search the quarters of Nolan. He finds detonators and pamphlets linked to right-wing group Home Guard who were behind the events of The War Prayer. Nolan's bomb had detonated early by accident.
It's a pretty straight run to the finish from there. They realise Home Guard are behind the plot, and that Cutter planted the evidence in Garibaldi's quarters while searching them. He also rigged the doors of the fighter bays to explode on opening, which is aborted with the time-honoured one second to spare. The episode ends with Garibaldi and Kemmer reconciling. They promise to keep in touch, but like so many incidental characters we never hear from her again and it's likely she doesn't make it past the end of the season.
This isn't the last time we'll see personal vendettas running the plot - or even the last time this season. It's also not the first or last time Sinclair uses his interpretation of the rules and regulations to protect the station and its people. He's going to do it again in the very next episode, in fact.