It seems to me like they had 1.5 episodes' worth of material, and they had to stretch it out to 2 with padding, to make the full two-parter. Part I is mostly set up for Part II where the real action is. I'm only going to talk about what stands out, so it's going to make it sound like I enjoyed this two-parter more than I actually did. So, keep that in mind. Anyway...
The A-Story: Fighter Escorts, supervised by Ivanova, find an old Automatic Defense System found on the surface of Epsilon III. It's a threat to the station, but it's also a First Contact Situation. When Sinclair and Ivanova visit the Defense System on Epsilon III, they did a good job of making the sets look gigantic. I'm betting the set designers used a combination of forced perspective and matte paintings to make the interiors look so large. When Sinclair and Ivanova find an alien named Varn hooked up the controls for the Automatic Defense System, the alien says he needs their help or everyone will die. Varn's dying and, when he dies, the Defense System will be operated by no one, the planet will be unregulated, then Epsilon III will explode and take Babylon 5 with it.
Ivanova, after says they have to get out of there, and off of Epsilon III, but Sinclair doesn't want to leave the alien behind. "I know. It's a Russian thing. When we do something stupid, we like to catalogue the full extent of our stupidity for future reference." They rescue the alien, make it out in time, and bring him to the Medlab on Babylon 5. And it's official: I like Ivanova's Russian references better than Chekov's!
While Sinclair and Ivanova were rescuing the alien from Epsilon III, an Earth Alliance heavy cruiser is what came through the jumpgate. Captain Ellis Pierce of the Earth Alliance Starship Hyperion is there to take control of the situation. Sinclair and Pierce are immediately at odds. Sinclair believes he still has full jurisdiction and he thinks Pierce is only making things worse by waving a big stick in front of everyone on the station.
Love the stand-off between Sinclair and Pierce when Pierce wants to Epsilon III, Sincliar wants him that he'll put everyone on Babylon 5 in danger by going there, Pierce doesn't listen, and Sinclair prepares to fire on him. But then it becomes a non-issue. Pierce stands down, then they have to fight renegade aliens who claim Epsilon III for themselves, but Varn says they have no claim to the planet. Both of these ideas could've been episodes of their own, but not the case here.
During the showdown between Sinclair and Pierce, I almost expected things to go as badly as they did between Commander Adama and Admiral Cain on BSG (the '00s version, so there's no mistake). "I'm getting my men." It never got to that point, and I'm glad it didn't. I feel like I'd rather have Sinclair and Pierce on the same side, since -- unlike Cain -- I think Pierce has good intentions.
Draal, an old Minbari who's a friend of Delenn's, take Varn's place, stabilizes the defenses of Epsilon III, saving the day, and keeps any hostile forces at bay. The End. During Part I, I thought his part of the story was just filler, but I see they were establishing his character before he took this step in Part II.
The B-Story: Trouble on the Mars Colony. All communication cut off. An uprising against the Earth-appointed government. Garabaldi has a former lover who lives on Mars. He's worried she might be dead. More than worried. He's thinking about it his every waking moment. And it's a lot of waking moments because he can't even sleep. He tries to go through any channel he can, to no avail, and tries to think of anything he can do just so he feels like there's a situation he has control over since he feels so helpless about what's going on back on Mars.
At the bar, the situation has really gotten to Garibaldi. When the news reports that President Santiago wants to send in troops to subdue the Mars Rebellion, we get some loud-mouth asshole who says the Martians are getting what's coming to them. He sounds like he'd fit right into an Internet Comments Section. Garabaldi isn't having it and smashes this loud-mouth's head onto the table top a few times. I'm betting that's exactly what JMS has wanted to do that to at least one person like that at a bar. Or online. The discourse is about the same a lot of times.
The twist ending comes when Garibaldi is finally able to get in touch with his ex-girlfriend, he sees that she's alive, but then she says she's married and expecting her first baby. I should've seen that coming a mile away. She has her own life she's living that Garibaldi doesn't actually know anything about.
By the end, they say things are under control on Mars, but I don't believe it. There's more coming. Guaranteed this is only a lull.
Summing Up: This dragged too much. There are good parts, like what I mentioned above, but they could've made this a tight single episode and still gotten everything they wanted to get across intact. Part II is better than Part I, but I'm going to average this out and give the whole thing a 6.