We Need to Talk About Joe Goldberg’s Glass Cage in You Season 4

Spoilers ahead.

It seems all serial killers on TV have their favorite methods and go-to tools. While Dexter favors strapping his victims to tables with Saran wrap, Joe Goldberg has a penchant for slick glass cages with a lock and key. Heck, he’s even been known to deck out his glass cages with cozy rugs, soft furnishings, and classic books, of course.

However, as Joe moves from New York to Los Angeles and now to London throughout the series, one question many You viewers continue to ask is, how in the hell does he transport his custom-made glass boxes? First, it traveled with him across the country, and in season 4, to the other side of the world. ELLE.com caught up with showrunner Sera Gamble to find out how Joe sources his terrifying traps, and how he imported them to London without anyone noticing.

What are Joe Goldberg’s glass boxes?

Fans of You will be extremely familiar with the glass boxes that Joe Goldberg uses to trap his victims. The cages have been an important part of Joe’s oeuvre, originating in Caroline Kepnes’ book series, on which the show is based.

Originally, the glass box housed rare books in the basement of the store Joe worked in. The book store’s owner, Mr. Mooney, would lock Joe in the cage as a young boy to punish him. As an adult, Joe started using the lockable box as a torture chamber for his own victims. Air-controlled to keep rare books at the perfect temperature, Joe can supervise and alter the environment from afar.

One might assume that Joe would leave the glass cage behind when he moved from New York to Los Angeles in season 2. Instead, he managed to ship the parts, reconstructing it in a storage locker, where he held some poor souls. Of course, reconstructing the cage wasn’t easy, with Joe noting in episode 2, “Without Mr. Mooney’s help it took two full days to put this thing together. Stressful doing it with Will watching me, tied up. Three quarter-inch plexi’s a beast. Yet those edges are a thing of beauty. I gotta think Mooney would be impressed.” And by season 3, Love and Joe were building a glass cage together in the basement of their bakery in Madre Linda, and no one batted an eyelid.

Unsurprisingly, Joe finds a way to erect another glass cage in London, this time in an underground lair in an abandoned building. But how, exactly, does Joe Goldberg transport his trademark structure halfway across the world?

Where does Joe even buy this stuff?

Gamble has been asked more than once how Joe Goldberg sources his glass cages. “First of all, you’d be surprised what comes in a kit on the internet,” she tells ELLE.com ahead of the release of You season 4 part 2. “Before we settled on this glass cage, we looked at all different kinds of cages, made of all different materials for all kinds of really horrifying uses. And some of them come in a kit.”

Basically, it would appear that Joe Goldberg’s proclivities are more common than you might have thought (which is terrifying). “There’s nothing wildly rare and hard to source about that cage,” Gamble says. “And he’s built one several times at this point. So he knows what pieces he needs from Home Depot.”

If you were wondering about the price of Joe’s special boxes, a reporter at The Tab did an extensive deep dive, even contacting companies to find out how much it would cost to have a glass cage specially made. While most of the people they contacted thought the request was somewhat creepy—and rightfully so—one person did reply and quoted somewhere in the region of $70,000 to $95,000. Basically, Joe Goldberg’s tools don’t come cheap, unless there’s a special serial killer discount warehouse we’re unaware of.

But how does no one notice Joe building a glass cage in central London?

As for how Joe manages to build his cages in pretty public areas without anyone noticing, Gamble points out that he blends into the surroundings, and his attractiveness helps him get away with it, too (just like with his murders).

“You watched him [carry glass panes into a building] with his wife in the previous season,” Gamble explains. “It just looked like part of the decoration of the bakery. Nobody asks themselves, ‘Those two attractive, happy, young, middle class white people who are bringing this big pane of glass into the bakery, I wonder where it went because I never saw it.’ Nobody suspects them.”

While London is new territory for Joe, he somehow plans out where to erect his glass cage. “If you look at the street that the bomb shelter is on, it’s full of businesses,” Gamble says. “If you see somebody with a hand dolly, you’re not going to ask any questions. This is really Joe’s area. He knows how to look like he belongs.”

When it comes to Joe’s acquisition of multiple glass cages, the You writers’ room is dedicated to getting the smallest details right. “One of the most important jobs on a TV show is the writer’s assistant,” Gamble explains. “They sit all day in the writer’s room and they take notes. … There’s a lot of times when we’ll turn to our writer’s assistant, and just be like, ‘So is it true that you can dissolve a body in cat litter?’ And then that’s her search [history]—the kinds of cookies she’s leaving, the kind of ads she’s going to now see, her search history if someone goes missing in her neighborhood.”

As real as Joe’s glass cages may seem, we’re definitely hoping that they safely stay on Netflix.