Spoilers for both The Blacklist and Blindspot's fall finales.

Big thanks to theblacklister23 aka pl3as3-tak3-m3-t0-w0nd3rland on tumblr, because she just enabled my damn need for this crossover.

Kurt knows that Patterson and her team (although it's most likely just Patterson) have solved the next tattoo when he sees the woman come hurrying over to him, a triumphant light in her eyes as she brandishes a printout at him.

"Got a new one!" she declares, and the team starts to follow her back into her lab to review the info. "This one looks like it's going to require a road trip."

Honestly, he's glad she finds some kind of happiness in her work after everything that has happened with David. From time to time, he catches her in her lab staring off into space, and thoughtful, but she seems to be healing. Seems to be seeking friendship with Jane to help.

At least Jane is open with her, from what he's seen. He's been worried; since Jane kissed him a week ago, she's been distant, evasive even. At first, he thought it was Zapata's resignation that had bothered her, but now he's certain that isn't the case. He's trying to respect the fact that he should be trying to be more professional with her anyway, but he honestly wonders why she regrets what happened.

Jane's already in the lab by the time he enters, and when he makes eye contact with her, she holds herself a little straighter and focuses on the screen.

There are numbers and letters concealed in striping lines in the image there.

"I don't recognize this one," Jane says with a frown, scanning the photo for clues to its location.

"It's hard to see, under your arm and towards your back," Patterson raises her own arm and gestures to the location. "But this," she circles an area on the screen with her finger, "is what's interesting. This tiny mark here? It's an old tattoo. It's so small and darkish brown, someone marked it as a birthmark at first...that someone has been formally reprimanded but once I found it, I noticed the cypher here, and we were able to use our last case's tattoo to solve this one."

The shape is almost a 'Y', but blotchy.

Patterson advances the slide and they're presented with a map view of an old, large building, tomorrow's date, and '1212-654 White Bear'.

The Forensics leader leans against a table and took a deep breath before launching into an explanation. "So this is an old abandoned Post Office in DC, but when I reviewed sat footage from the last week? There's been a lot of activity at the site, a lot of cars in and out. There's been activity here for two years, but I can't find record of a business buying or leasing the space. Lots of big vans, cars...it's a mix. Big operation. But it really gets weird when you look at that last segment."

"That looks like a call-in ID code," comments Reade when she points at the last bit on the screen, and Patterson dips her head in quick acknowledgement.

"That's exactly what it is. There's sections of the FBI database even I'm not cleared for, and I found them while I was working on this, but that ID? It was used by Agent Elizabeth Keen, better known as-"

"-Masha Rostova," Kurt finishes, voice hard. "Killed the Attorney General and bombed an OREA site." He'd been relieved to hear her death announced; he'd had a friend in that substation. The news of his death had come out of nowhere and he'd called to check on the guy's wife, went to the funeral, hugged his son.

"But why is a dead double agent's name on my arm?" Jane asks, eyebrows knitting together. "Do you think this is another bomb? Do you think she planted it before she was killed?"

Patterson's shoulders rise in a slight shrug. "That's what we're trying to-"

"-But what if tomorrow is too late?" Jane continues, her rough voice tense, faster than normal. Reade gives Kurt a look, letting him know he has picked up on her anxiety as well. "We should go now. We should stop it."

"We don't even know what it is," Reade argues.

Jane turns to him. "Does it matter? We can't do anything from here."

Kurt straightens from his spot leaning on a desk and tries to gain command of the situation before Jane's obvious unease escalates.

"Patterson, you were able to decipher the tattoo ahead of its schedule, and it's bought us time, might save some lives. Good work." He turns to the others, crossing his arms and gesturing to the door with a jerk of his head. "We can prep to be in this location's area, but Patterson, I want you to keep working on getting us more intel and what we're up against at the site while we're in transit."

In the hallway, he tries to ask Jane if she's alright, if there is anything she wants to talk about.

"I'm fine," she assures him, already turning to continue down the hallway, away from him.

He's not convinced.

One of Aram's assistants gives his stool a harsh nudge with the toe of his shoe on the way by.

"Did you just kick me?" Aram sputters, incredulous and immediately minimizing the window with the security cam feed.

"That would be rude, since you're my boss," answers his assistant. "I accidentally bumped your chair, which served as an unintentional reminder that you can't spend all your time staring at Rostova with that guilty look."

Aram opens his mouth to reply defensively, but he's always been so horrible at lying what was the point?

"We caught the bad guy," his assistant reminds him pointedly before retreating to his own computer.

Aram doesn't share his simple conviction. He takes a deep breath and lets it out long and slow exhale. Good guys and bad guys and who is who seems really complicated these days

Samar is gone. Liz and Dembe are here and imprisoned. Reven Wright had apparently been with the Cabal and attacked Hitchin, who has been making increased appearances at the Post Office. Mr. Reddington hasn't attempted to contact him, which is probably smart because they're probably monitoring his phone and internet activity, and he feels like he genuinely screwed up by letting Ressler know where Liz was.

The Task Force has spent hours questioning both of them, but neither is saying anything. Dembe is his typical silent self, and Agent Keen simply sits there in the box, staring blankly, sadly out at the room.

This sucks.

He's trying to keep himself busy with a half hearted search of the burner phone number they had found on Liz when the alarm went off on his computer.

"No. No no no nonono. Uh Agent Ressler?" he calls out, unable to take his eyes off of the computer screen as he furiously works to curb the attack now infiltrating their security system. "We are being seriously hacked right now."

The tech team immediately start to try to shut down their network connections, in a sudden burst of activity.

Very similar to the burst of activity as a group in tactical gear sweeps in. There's a few minutes of absolute chao where Ressler, halfway to Aram's station with his hands on his hips, immediately draws the weapon there and turns on the nearest person who has rushed into their space, and there's shouting and Aram has his hands up because he seriously does not want to have to shoot someone again and there's a lot of shouting of 'Freeze FBI' going on and-

Wait. The people who just broke in are saying it too.

From the look on Ressler's face as he and the rest of the Task Force refuse to stand down, he's just as confused as Aram. When Donald gets confused, he gets angry, and Aram hopes this doesn't end with bloodshed.

And then insurgents' leader is relaxing his stance, and so is their deputy director.

"Weller?" Ressler asks, voice rising with disbelief.

"Been a while since Brussels," the stranger responds warmly, like they weren't in a standoff with guns in one another's faces, and Aram questions his life choices for the umpteenth time. "Want to get your team to stand down so we can figure out what's going on here?"

There's a lot to noise as guns are holstered and people relax, and Aram slumps down in his seat with relief.

Maybe he needs to find a new job.

Jane and her team sweep down a staircase and around a corner. They've been able to disarm and contain the security team in the building with minimal injury, since Patterson took their security and communications system down, but they still can't be too careful.

These people aren't a group of paid thugs; they seem trained. Efficient. They've got military-grade weapons and gear, and half of the team she was assigned to for the siege are still engaged on an upper level in friendly fire, providing cover for a few of them to advance.

Reade is still with her, off to her side. They roll the flash bomb first before they sweep around the corner and into a large, open warehouse-like space.

Two guards. Easily taken down and disarmed. They want to keep as many of them alive as possible for questioning since they still haven't found much information out about this group.

They're claiming they're FBI, but she knows that could be a lie. Or they're misled. She ignores them.

The security team was protecting whatever is in this box, she realizes as they approach it. It's lit from within, bright orange-yellow old florescent lights. There's something moving in there.

They advance carefully.

"Weller," Reade says quietly next to her, lowering his weapon slightly. "Rostova is alive." He doesn't even wait for the question before replying to it. "Looks like she's their hostage."

The blonde woman in the box leans against the glass to look out them, squinting from the glare of the bright lighting on the scratched glass of her strange cell.

There's silence for four heartbeats too long, and Jane repeats his name, never looking away from the woman before them. "Weller? You okay?

"She's not a hostage," Weller finally replies. "This is a FBI black site. Everyone can stand down."

Rostova is alive. Another lie. Another secret. Jane looks at the woman on the other side of the glass from her and lowers her gun.

Rostova is staring back at her, cautious, her breathing accelerated, but Jane sees determination in her, sees the Russian woman's blue eyes flicker to Reade's firearm and her own, knows she must be able to think creatively and fast if she was able to infiltrate the FBI for so long.

Jane could just as easily be in the box instead.

Her eyes are drawn to the woman's hands, flattened against the glass.

There's a big, raised scar on Rostova's hand and wrist. It's red, and old, but Jane recognizes it all too well.

It matches the mark they found on Jane.