A wounded man rushes through the sewers of the Mars Colony, where he meets up with a Ranger. Just before the man dies, he hands the Ranger a data crystal. "Take it to Babylon 5. Tell them... tell them it's not safe." The Ranger takes the data crystal and escapes back into the sewers, just as the people pursuing them catch up.
Captain Sheridan and Garibaldi meet in the bathroom and begin a conversation. After making sure it is clear, Garibaldi activates a bug-jamming device and asks Sheridan if he gave any more thought to the idea of bringing Talia in on their conspiracy. Sheridan agrees to the idea, and they make plans to tell her in a few days.
Talia and Ivanova are eating, musing over their new friendship. Each blames the other for the difficulties in achieving the friendship, but their conversation is interrupted by a call from C&C for Ivanova telling her that a ship arrived through the jumpgate, and has done nothing since its arrival. Ivanova goes to C&C to investigate. As she leaves, Talia tells her that, due to a problem in her air recycling system, she needs to find a place to stay for a few days. Ivanova offers her quarters.
Ivanova determines that the ship was hit, and tries to contact the ship. There's no response from the one lifeform on board. She orders the ship brought aboard the station.
Garibaldi tells Sheridan that the woman, Lyta Alexander, was Babylon 5's first commercial telepath, though she lasted only a few weeks. She scanned Kosh after the assassination attempt and discovered that Kosh saw Commander Sinclair as the murderer, which nearly ruined Sinclair's career, though he was later proved innocent. Garibaldi explains that she and Dr. Benjamin Kyle, who operated on Kosh, were recalled back to Earth, and Lyta was never the same after the scan.
Garibaldi tells Sheridan that, as far as he can tell, Lyta is correct in all that she said. Sheridan warns Garibaldi not to trust her, but Garibaldi says it is a gut feeling of his that she is telling the truth. Sheridan suggests that Garibaldi's aide may have been the mole, but there is no proof either way. Sheridan says that he wants to think about it overnight before making a decision. Garibaldi asks if Ivanova has come around, and Sheridan tells him that she hasn't.
Ivanova is working out her anger slamming cupboards in her kitchen when Talia comes in. Ivanova fixes some tea for them and asks Talia about Lyta. Talia tells her that they spent part of their early careers in intern programs. Ivanova asks if she feels that Lyta could be trusted, and Talia says that she thinks she can. Ivanova also asks where Lyta interned, and Talia tells her that she interned with the Psi Cops before becoming a commercial telepath. Ivanova tells Talia that she doesn't know who she can trust, and Talia agrees, saying that she feels that she can only really trust Ivanova.
Zack Allen enters Garibaldi's office and Garibaldi tells him to move Lyta to a more comfortable holding area, since she may be there for a while. As Zack leaves, Garibaldi asks about the Nightwatch armband Zack still wears. Zack says he feels it's easy money.
Sheridan can't believe that she hasn't been located, or even that the attack happened, because he had almost believed she was wrong. Sheridan doesn't understand who could have done it, since very few people knew Lyta was there, but Garibaldi reminds him that the sleeper personality was probably responsible. He orders Lyta put under protective custody, and tells Ivanova and Garibaldi that he wants to let her send the scan. Ivanova is obstinate, but Sheridan says that, under the current circumstances, if they don't know who they can trust and who they can't, they won't be able to function properly.
Delenn is in her quarters composing a letter regarding trade relations with the Lumati when she receives a call from Lyta. Lyta asks Delenn to meet her in Brown 3 in an hour.
Talia arrives at Ivanova's quarters to tell her that the air recycling system has been fixed, so she'll be returning to her own quarters. Talia asks her if everything is all right, and Ivanova says she doesn't want to talk about it. Talia asks where she went the night before, and though Talia offers help yet again, Ivanova refusts it, saying that her secrets might soon come to the surface and haunt her. "After you tell someone that you've been lying to them for years, maybe even putting them in jeopardy, how are you supposed to look them in the face again?" Talia tells Ivanova that there are people around who care, though Ivanova still has doubts. Talia reminds Ivanova that she is there for her.
Delenn meets up with Sheridan in a corridor and tells him that she received a message from Lyta. Sheridan asks where she is, but Delenn promised not to tell anyone. Lyta will return, Delenn says, but only if everyone is present. Sheridan tells Delenn to tell Lyta that he agrees to her conditions.
"Susan, why didn't you tell me this before? I thought we could trust each other."
"It's got nothing to do with trust. I've spent my entire life hiding this, Captain. It's not something you can just change overnight. It's hard enough telling you this now."
"You're right. I'm sorry."
"For as long as I can remember, my mother drilled three words into my head: 'Tell no one.' She taught me how to fool the tests given in school, transferred me from one school to another, always staying one step ahead of the Psi Corps. I'm probably not even a P1 - I've never been able to read anyone except my mother. I can pick up on feelings sometimes, I can block a casual scan, and I know instantly if someone's doing it. Nothing more. But that's enough for the Psi Corps to come pull you in!"
Sheridan tries to convince her that Lyta is not involved, though she is hardly convinced. He says that he believes Garibaldi, especially since he so rarely trusts anyone. Ivanova thanks Sheridan. "It's all this nonsense lately... some days, I don't even know who I am any more," she tells him. As she says that, Sheridan remembers the dream he had a few months earlier (cf. "All Alone in the Night.") As he starts to explain, he receives a message from C&C saying that Delenn has sent him a message: "Now."
Delenn brings Lyta to Sheridan's office. Sheridan tells Lyta that he agrees to let her send the password into the command staff of Babylon 5. She sends the password to Sheridan, but nothing happens. She follows up with Franklin and Garibaldi. Garibaldi frightens everyone by pretending that the password was a success. Though Garibaldi suggests they move on to Ivanova, Sheridan tells him that they will wait for now, as they have many other people to check. One by one, they bring the command staff into Sheridan's office, where Lyta, quietly in the background, sends the password to each. None of them possess the program.
"Go to hell," Ivanova responds.
Garibaldi can't believe that Talia could be the one. Sheridan says that it isn't her fault, and that she's been carrying the sleeper program around for years without knowing it. Their more immediate concern is how much Talia knows. She knows about the underground railroad, but they aren't sure about how much more. Franklin will be protected by the Psi Corps' desire to keep its squelching of the railroad a secret. In addition, Franklin and the others know about the sleeper program, which Psi Corps definitely wants kept secret. Garibaldi realizes that Talia knew a lot, and if Lyta hadn't come aboard, they would have told Talia about their conspiracy. Sheridan asks if there is anything they can use to defend themselves with, and Garibaldi thinks he might have an idea: When Talia mediated for Kosh and Abbut (cf. "Deathwalker,") Kosh was given a data crystal which he claimed contained "Terror. Surprise. Reflection. For the future." Garibaldi says he will have to check on it a little more before he can be sure.
Ivanova goes to "Talia" and says that she wanted to see her before she left. She doesn't blame "Talia", but hopes that some part of her will hear her. "Talia" says that the program was complete, and that the old Talia no longer exists. "Talia" explains to Ivanova the role she played inside Talia's head, whispering instructions to her while she slept. Ivanova believed everything, all the words that were meant to get Talia close to Ivanova and what she knew.
"You're right," Ivanova tells her. "The Talia I knew is dead." She leaves.