SPOILER ALERT: This story contains spoilers from Season 4 of “You,” now streaming on Netflix.

“You” can go home again: At the conclusion of Season 4 of the Netflix thriller, Joe Goldberg (Penn Badgley) is back in New York City, alongside his billionaire girlfriend Kate (Charlotte Ritchie) — sitting on top of the world.

He nearly died by suicide earlier in the episode, in some warped attempt at redemption. But by the finale’s ending, Joe, who’s has killed his way through London (in his fake identity of Professor Jonathan Moore), has emerged exultant. He’s fused with his murderous side, and seemingly happier than he’s ever been on “You.”

“I thought it was the only way it could go,” said Badgley during an interview for the Feb. 15 cover of Variety about where Joe ends up. “I thought it was brilliant.”

Heather Hazzan for Variety

Sera Gamble — the “You” showrunner, who created the series with Greg Berlanti (based on a book by Caroline Kepnes) — told Variety that any justice coming for Joe Goldberg will have to wait. “Unfortunately, while we all may desire to see this man punished, what actually tends to happen with men like this is that they don’t necessarily — karma doesn’t display itself obviously, as far as I can see,” she said of how the writers saw the ending of Season 4. “We were joking about it as his triumphant homecoming, where he ultimately would be able to come back and reclaim his name — reclaim his name, reclaim his family, meaning, his son that he left behind. And also be able to move through the circles in New York that he could barely even observe from afar earlier, because he was pretty poor when we met him.”

Charlotte Ritchie as Kate, Penn Badgley as Joe Goldberg. Courtesy of Netflix

Yes, Joe has emerged not only unscathed after reaching his lowest point, but victorious. Having set about trying to start a new life as Jonathan in Season 4, as a professor at a London university, he soon found out that there was a serial killer in his midst. By the end of Episode 5 of “You,” where Netflix divided the season in two, Joe thought that the killer was Rhys Montrose (Ed Speleers), a brilliant writer and upstart politician. Rhys, in Joe’s absolutely unreliable version of events, was setting him up as the Eat the Rich killer who was murdering members of the upper class social set that Joe had infiltrated.

But Joe, of course, is the serial killer. How could it be otherwise? He’s the problem; it’s him. In the show’s seventh episode twist, we learn that Joe barely even knows the real Rhys, and he’s imagined him as his enemy: Joe’s “you,” the person he addresses his narrative to in the template of the series, is, in fact, himself. (He discovers this fact after he murders a completely innocent Rhys.)

Four seasons into “You,” Joe’s “you” is him. “I think it’s the only way it could go,” Badgley said.

Gamble said the writers have been building up to Joe’s personality splitting. “Joe goes crazier every season. And if you if you trace back, he’s always been delusional in his thoughts,” she said. He’s hallucinated before, she pointed out, when “he saw another version of himself” in Season 3.

“We’ve been quietly building to the twist in the second half of the season since the beginning of Season 1 — we’ve always had this in our pocket as something we wanted to do: just make him go full crazy,” Gamble said.

Badgley was thrilled, though, that he wasn’t playing his darker half. Acting against Speleers as Joe’s split-off Mr. Hyde meant “we get to see the fun of it not literally being me playing me,” he said. 

Ed Speleers as Rhys, Penn Badgley as Joe Goldberg. Courtesy of Netflix

For Badgley, after three and a half seasons of delivering most of his lines in Joe’s voiceover, which he records in a booth alone, having a scene partner like Speleers’ Rhys was completely novel. “No one experiences how little Joe speaks as much as I do,” he said. “No one is aware, actually, of how little he speaks other than me — because I have to go and never speak!”

“It is true,” Gamble said. “There are many days when he shows up and he has no actual dialogue. Somebody is reading the voiceover, and Penn is moving his eyeline.”

Over a breakfast interview in Brooklyn, Badgley was amused when he remembered a conversation he’d with Ritchie at a party for the show, when she asked him how his day on set had gone. He replied, “‘Oh, it was nice, because I finally got to shoot a normal scene,’” Badgley recalled. “I realized that scene was waking up and deciding I had to kill myself, and speak to my split-personality figure in the kitchen. When I said that, I laughed like, ‘Oh, that’s a normal scene.’”

By the finale, Joe has realized what he’s done — that is, he’s killed a bunch of people, kidnapped his Season 3 love Marienne (Tati Gabrielle) and put her in a cage in the basement of a condemned building. He decides he needs to end his life. But really, he wants to kill Rhys, whom he feels plagued by.

“Yes, Joe is suicidal; technically what he’s doing is trying to kill Rhys,” Badgley said. “What he’s trying to do is to kill a killer.”

In the logic of “You,” and in the twisted mind of Joe Goldberg, this rationale makes sense to him. “He’s coming up with a logical solution to save people,” Badgley said. “This is the thing: He still actually wants to save these people!”

As Joe stands on a bridge over the Thames talking to Rhys, he appears to have faced the reality that everything Joe does, no matter what his intentions, leads to death. “Every time, I try: I make it perfect, it’s never enough,” Joe says in anguish, before he pushes “Rhys” off, and then jumps himself. (He survives, of course, and wakes up in a hospital with Kate at his bedside.)

Charlotte Ritchie as Kate in the finale of “You.” Courtesy of Netflix

“I think it does kind of feel like a redemption arc to the viewer,” Badgley said.

Badgley directed the show’s ninth episode, which neatly sets up the events of the finale: Joe wants to free Marienne but doesn’t know how, his student Nadia (Amy-Leigh Hickman) has discovered Marienne in the basement, and is onto him — and Joe is really sick of Rhys badgering him. By the finale’s conclusion, Joe has framed — and killed, of course — Nadia’s friend Edward (Brad Alexander), setting him up to take the fall for the Eat the Rich killer. He’s also framed Nadia for Eddie’s death. Joe calmly explains to her that this way, she gets to survive, even though she’ll go to prison, and in the show’s final moments, Joe says in voiceover that Nadia didn’t speak in her own defense at her trial.

Will Nadia come get Joe’s ass in a presumed fifth and final season of “You”? “She’s great,” Badgley said, while also claiming he doesn’t know what might happen. “She’s the most plausible.”

“You” is a dark satire, and a layered character study about a promising young man so damaged by childhood abuse and neglect that his sense of right and wrong has become completely gnarled. Which makes it fertile ground, apparently, for not just one, but two Taylor Swift references in the final two episodes — one of which is an Easter egg.

In the episode Badgley directed, when Joe has learned that his Rhys side kidnapped Marienne — rather than let her go back to Paris, as Joe thought he had — and he figures out where he’s stashed her, he can’t get the code to work on the cage. “One, two, one, three, eight, nine” he intones several times, becoming frantic. The significance of those particular numbers? “The code to the cage is Taylor Swift’s birthday,” Badgley said with a laugh.

But Joe isn’t a Swiftie, no matter what the cage’s code is — and no matter what Netflix’s Twitter account claims.

“I think, unfortunately, he would despise her,” Badgley said. “Because she’s successful and blond, maybe? I don’t know, but I think he would.”

“You’s” second Taylor Swift moment is onscreen and obvious in the finale. After Joe has resolved things in London, and seemingly confessed all to Kate, “Anti-Hero” plays over the wrap-up montage about what happens to the characters — which then leads us to Joe’s return to New York City, where his past misdeeds (aka many murders) have been wiped clean and erased, as funded by Kate.

“Anti-Hero,” of course, is significant in Badgley’s world as the song that he used for his first TikTok, in which he plays two versions of himself. (Perhaps a nod to Joe’s split personality in Season 4.) Badgley filmed that TikTok — which went viral, and was endorsed by Swift herself with an “OMG!!!!🤩” in the comments — in late October, the week her album “Midnights” came out.

Did he think they used the song, with its Joe-appropriate title, because of his video? Badgley wasn’t sure, he said, but he thought so: “I’m almost certain that they did it because of that,” he said. “It’s a perfect nod.”

Gamble confirmed Badgley’s guess. “It occurred to me while I was watching the music video that we should try ‘Anti-Hero’ for the big montage,” she said. “Of course, I also immediately remembered Penn’s first TikTok — hard to resist the little meta wink, and frankly the fact that Taylor had commented on the TikTok made me hopeful that we had a shot at licensing the song even though it was brand new.”

Courtesy of Netflix

Netflix hasn’t yet renewed “You” for a fifth season, but the show has continued to do well for the streamer. Its publicly available statistics for its worldwide Top 10 lists show that the first half of Season 4 reached the Top 10s in 90 countries, and it was in Netflix’s Global Top 10 for three weeks. Upon its March 9 release, the second half of “You” Season 4 immediately shot to No. 1 in the United States.

The fourth season of “You” — with its initial whodunnit framework ­— was different in tone from the previous three seasons. But Badgley said he feels good about how it ends. “They always manage to stick the landing,” he said. “The triple axel of every season finale is very hard.”

And Gamble is hopeful about bringing Joe Goldberg’s story to completion in a homecoming. “We would love to do the return to New York,” she said.