This is the Saul episode we’ve been waiting for. Mandy Patinkin is in fine, fine form in the fourth installment of “Homeland’s” fifth season, “Why Is This Night Different?”

SPOILER ALERT: Stop reading if you haven’t seen the Oct. 25 episode of “Homeland.”

The action in this episode, written by Ron Nyswaner and directed by John Coles, covers a whole lot of territory, from ripped-from-the-headlines geopolitical chess games in Syria to the tenderest of moments between Carrie and Quinn to the curveball of casting suspicion on the allegiance of a key character, Miranda Otto’s Allison. And Russian elements clearly emerge as the key bad guys. Wonder if Vladimir Putin and Bashad al-Assad are keeping up with this season?

Saul is working overtime to implement the CIA’s covert plot to overthrow Syrian president Assad and replace him with the military’s Gen. Youssef, played with a cool intensity by Igal Naor.

The pair’s discussion in the garden setting of the cold-hard calculus of the CIA’s plan to install Youssef as the successor to Assad is remarkable for its discussion of real-world leaders, real-world terrorists (the Islamic State) and real-world politics (Russia’s support of Assad). Saul proves himself a master manipulator in convincing the stubborn general that he really has no choice but to agree to the CIA’s plan.

And of course, the plan Saul lays out to Youssef comes a day or so after Saul has assured the Israeli ambassador in Berlin that the CIA is “out of the business” of instigating regime change in the Middle East. Undoubtedly Saul’s fingers were crossed under the Seder table. Or perhaps he really didn’t know it was a go until he got the “greenlight” from F. Murray Abraham’s CIA chief Dar Adal.

“This is your plan for Syria?” Youssef tells Saul with thinly veiled scorn.

“It’s the best one on the table,” Saul replies. It’s probably the truest statement he makes in the entire episode, except at the very end.

When Saul promises that Youssef will have the full support of the U.S. in establishing free elections and Democratic reforms, you can feel the weight of so many past failed U.S. interventions on both of their minds. Saul notably doesn’t really answer Youssef’s question about whether that support will come with troops and more money. He doesn’t have to.

But there’s no time for a quagmire with this particular operation. Youssef’s private plane, stocked with Saul’s promised $10 million in cash, blows up shortly after takeoff, a big boom that strongly suggests that the CIA’s Berlin station chief Allison is in double-agent mode. But the fact that she could be working in cahoots with the Russians still isn’t as big a shocker as the fact that she has become Saul’s lover, as we learned in episode 3. (Where oh where is Saul’s wife Mira?) However, maybe that coitus is actually Saul working Allison (a guy’s gotta do what a guy’s gotta do) because he knows something’s up with her?

Meanwhile, intrepid exiled American blogger-activist Laura meets a kindred spirit in Sabine, a German blogger-activist under house arrest, as the hunt for the rest of the hacked CIA documents takes another twist. Hacker Krupin gets in way over his head in trying to score big bucks by selling copies of those documents to the Russians — and pays for it with the his life and that of his girlfriend. Janina Blohm-Sievers as Sabine is another fine example of great casting (particularly of femme roles) in “Homeland” this season.

The explosion at the end connects the Saul story with Carrie’s adventures in the episode, which takes a page from Snow White and the Seven Dwarfs in casting Quinn as the Huntsman. Quinn is sent to kill Carrie but of course he can’t kill Carrie, because Quinn has truly become the moral center of “Homeland.”

The bizarre-ness of Quinn and Carrie’s star-crossed romance is reinforced in two tender moments between them. The first is when Quinn strokes her cheek while smearing his blood on her face to take the picture that’s meant to convince Saul (?) that Carrie is dead. The second is when Quinn’s head drops on Carrie’s shoulder while she’s bandaging him after he’s ambushed by a Russian muscle man after dropping off the Carrie photo in the post-office box.

Carrie tells Quinn she “never stopped looking for him” and never stopped thinking of him even during her two years in Berlin. That doesn’t really ring true, but neither does Quinn’s weary reply: “That doesn’t matter now.”

Carrie and Quinn also have a uniquely “Homeland” discussion about parenting while he forces her to come to grips with the idea that she may never see her daughter again.

“If you want Franny to be safe, you have to be dead,” Quinn tells Carrie, as she trembles her way through a video message that presumably will find its way to Franny, who was sent back to her aunt in the States in episode three. (In the video we learn that Franny, aka Francis, was named after Carrie’s father, Franklin.)

Carrie’s response reminds us that Quinn also has a child. When Carrie asks how it was for Quinn to bail out on his family responsiblities, Quinn curtly replies: “Not everyone’s fit to be a parent.”

Carrie also take a cue from “The Americans” in donning a scruffy brunette wig that gives her a touch of Jane Fonda in “Klute.” Carrie insists on accompanying Quinn the post-box drop so she can see for herself that Saul was behind the directive to wipe her out. She may have been off the meds but she’s still pretty savvy — she doesn’t really buy that Saul would send Quinn to kill her because Saul would know better than to expect Quinn to pull that off.

Naturally, Carrie is in position to save Quinn after he’s shot by the Russian. And she has the presence of mind to grab said Russian’s smartphone and snap a picture of his slumped body in the BMW before racing off to aid Quinn, who refuses to go to a hospital. When she tells him the good news that there’s an exit wound in his belly, it seems an apt characterization of her predicament as well.

The only telephone number on the dead Russian’s smartphone is one that rings Allison, who is on the tarmac with Saul watching Youssef’s plane take off. She steps out of earshot from Saul to answer it with a telling “Da.” There’s of course the possibility that Allison was running a CIA-approved con game with the Russians, but the lack of surprise on Allison’s face as the plane disintegrates overhead makes us all think otherwise.

Saul speaks for viewers in delivering the last line of the episode: “Oh my god.”

“Homeland” airs Sundays at 9 p.m. on Showtime.