Claire Danes plays Carrie Mathison in “Homeland.” (Didier Baverel/Showtime)

This post discusses the Nov. 2 episode of “Homeland”: “From A to B and Back Again.”

“You have a real gift for this,” Tasneem (Nimrat Kaur), the Pakistani agent who is blackmailing Dennis Boyd (Mark Moses), tells him when he turns over the evidence that Carrie Mathison (Claire Danes), the new CIA station chief in Pakistan, is using psychiatric medication. “I guess everybody’s good at something,” Dennis tells her.

The reason Dennis is good at stealing information from desks and snooping through trash is that he is desperate and more than a little bit destroyed himself. And “Homeland” has always had at its core the idea that what makes a person useful in the covert, often nasty world of intelligence are also the things that risk destroying not only operations but also the asset’s life. For Carrie, that has been her mental illness and her ability to forge profound connections to sources; these help her see and learn things that no one else can but also render her emotionally vulnerable and unable to pull back.

“From A to B and Back Again,” in which Carrie’s hope that she can both use Aayan (Suraj Sharma) and protect him is violently disappointed, is the strongest, clearest explication of this idea that “Homeland” has put in a long time, maybe ever.

The episode reveals that, much like Carrie’s feigning of a resurgence of mental illness with a dedication that landed her in the hospital last season, her affair with Aayan has been marked by clear strategic thinking as well as a genuine emotional attachment that enabled her to get valuable information from him. After giving him a passport and walking-around money, she staged the watcher at Aayan’s university housing and an attack on the safe house so he would run to his uncle.

Carrie’s lecture to Fara (Nazanin Boniadi) after Carrie sets Aayan on the run may be unfair, but she is not entirely wrong.

“You know what I’d like to hear from you for once? I’d like to hear how you can help our effort, our collective f—— effort to make our country safe. Do you think you could manage that?” she demands of the younger woman, who may disapprove of Carrie’s methods but has not found a more effective alternative to them or taken on the ugly work herself. “You know what else, actually, while we’re on the subject? If you, or Quinn, or you and Quinn have problems with what I’ve done with the boy, none of it would have been necessary if you’d just done your job. You were supposed to recruit him. I had to go in after you f—– that up.”

Fara and Quinn (Rupert Friend) find Carrie’s methods distasteful, yet those methods produce a closeness that allows her to ask sources to do risky things and enables her to make good operational calls that would be impossible for others.

“No way he’s prepped for this,” Redmond (Michael O’Keefe) tells Carrie as they watch via drone as Aayan faces an unexpected checkpoint. “No. But I know him. He’s resourceful,” Carrie tells him. And she is right. Aayan bribes his way out of the potential disaster and continues on to his uncle. Later, after Carrie has to tell Aayan she loves him to keep him on the line, she wants to know what Redmond, a reluctant convert to her leadership, thinks.

“When you came back from DC, we all thought Hassiam Haqqani was dead,” Redmond tells her. “Now we’re about to get him for real. You made that happen. I guess that’s what I think. Mostly, anyway.”

When Haqqani (Numan Acar) evades them again, it is not because of Carrie but rather because of Haqqani’s cleverness: He uses Saul (Mandy Patinkin) as a human shield and, knowing the CIA is watching, shoots Aayan. Carrie, who tried to call in a drone strike even at the cost of Saul and Aayan’s lives, and Haqqani, in executing his nephew, show a clarity and unsentimentality that “Homeland” itself failed to exhibit in the show’s first season, when the showrunners decided to keep Nicholas Brody (Damian Lewis) alive.

“Homeland” has a structural problem: At the beginning of each season, it must undermine our faith in Carrie and diminish our pleasure in her company so that we, along with her colleagues, will be surprised by her latest gambit. But for the first time in a long time, “Homeland” pulled off a reveal that made the irritation seem worth it, one that explored the benefits and dreadful potential costs of Carrie’s approach to her job with a clarity that is both terrible and terribly exciting.