"What happened here?" Kelly asked as he took in the state of disarray the apartment was in.

"That's what I was hoping you could tell me," Voight said as he shut the door behind them.

"What happened to the window?"

Hank let it slide that he'd already told Severide his theory for what had happened here. It was obvious everything was still too much of a shock for the bullheaded firefighter to take in at one time, if Gabby's murder alone hadn't been too much for him to deal with, this certainly pushed it clear off the edge.

"Somebody broke it to get out, but the door was standing open when we got here, so why do you think that is?" Voight asked.

"I...don't know," Kelly said.

"Take a look around, notice anything out of the ordinary?" Hank asked.

It was a slow search. They took it room by room and Severide looked over everything, but he didn't seem to have any better idea what they were looking for than Voight did.

"What am I looking for?" he finally asked Voight.

"Well for one, where did the drugs come from? If he's been on all the stuff in that report, for as long as he has, they gotta be stored somewhere," Voight said. "You said he doesn't take drugs, and we didn't find anything but the normal stuff in the medicine cabinet. You got any idea where anybody would be hiding that stuff around here?"

Kelly turned towards the sergeant and glared at him.

"Yeah, I know about you doping yourself after breaking your neck...where would you hide that stuff?" Voight asked.

Severide continued to glare at him for a minute, before finally responding, "You know too much, you know that?"

"Why do you think they call us Intelligence?" Voight merely replied.

Kelly headed to the kitchen and asked Voight, "For being so smart, you only checked the medicine cabinet?"

"At the time we had no reason to suspect Casey was on any drugs except for the flu," Voight answered. "The docs say his seizures in the ambo were an interaction of those drugs plus whatever was in his system. And now we know why."

Kelly looked through the cabinets and didn't find anything, then went over to the fridge. Casey wasn't good at keeping the fridge stocked aside from beer and leftover pizza. There was a box of wine sitting on the top shelf, funny, he thought Gabby had more expensive tastes than that. He pushed it to the side to look behind it, and the box rattled.

"What the?"

"What is it?" Voight asked.

Kelly grabbed the box, it had something in it but was far lighter than a bag of wine. He pulled open the top flap and just stared at the contents.

"Severide, what is it?"

Kelly dumped the box open on the table, syringes and small vials spilled out and rolled across the tabletop. Voight picked one of the vials up.

"Insulin...you were saying?"

"It doesn't make sense," Kelly said. "What would Casey be doing with that?"

"What would Gabby be doing with that?" Voight asked.

"You can't-"

"You saw the video, you saw the photos...you think this was beyond her abilities?" Voight asked.

It was obvious from the wide eyed look on Severide's face that he couldn't even begin to grasp what Voight was getting at.

"Severide, you're EMT certified...what happens if a non-diabetic takes insulin?"

Kelly blinked, and slowly rolled off what he knew. "It creates an overdose of insulin which eliminates the glucose in the body which drops the blood sugar levels...and...and..."

"And what symptoms would somebody experience with that?"

There was a pause, before Severide reluctantly counted off, "Shaking, sweating, dizziness, weakness, headaches, tremors."

"Sounds like the flu," Voight said.

"Oh God," Kelly moaned as he ran his hands over his face, "this can't be happening."

"And could also result in fainting, coma, and death, right?" Voight asked.

"This can't be happening," Kelly repeated, "it doesn't make sense, why would Ga-why would anybody do that?"

All Voight said in response was, "For a firefighter with over 15 years on the job, you show a frightening lack of critical thinking. Come off it, Severide, you've seen stuff like this before."

Kelly shook his head. It didn't make sense, it couldn't be possible. Gabby and Casey were married, they were in love, what Voight was suggesting, didn't happen when two people loved each other. He was wrong, he had to be wrong...but the evidence of something was staring up at him from the table. He knew Voight was right. Casey wasn't diabetic and neither was Gabby and if either of them were, nobody would hide their insulin in a damn wine box.

"It can't be right," he said, more to himself than the sergeant. "Something has to be wrong here."

Voight could appreciate the difficulty of what Kelly was faced with here, but he knew their work wasn't over. He reached over and gripped the firefighter by his shoulder to force him to focus, "Where else?" The fact was they still had a whole pharmacy's worth of drugs to find and he knew they must be close by.

Kelly forced himself to pull himself back together and resumed his search. On top of the fridge were a set of old metal canisters for storing flour, sugar, coffee, etc., it seemed too obvious but he knew nobody had any reason to use them. He grabbed the biggest one on the end and heard something rattle in it.

"Oh God."

Voight looked and saw several bottles of pills stashed in it.

"What...why would...what possible reason would Gabby..." Kelly couldn't even bring himself to finish that thought. "It can't be right, we all had a drug test last month, everybody passed."

"Uh huh," Voight replied, "And they had one back in 2012 when you were self medicating, and you passed, right?"

Kelly's eyes widened. "You think Gabby..."

"If she's not taking this stuff herself, she could pass the test for both of them," Voight pointed out.

"But why?" Kelly asked helplessly. "Why would she do it?"

"Casey didn't want her filming him in the shower...you think he would've approved of her taking his picture in bed if he'd been awake?" Hank asked him.

"It still doesn't make sense, what's it all mean?" Kelly asked.

"I don't know," Voight admitted as he shook his head. "Hopefully we can find the answer here, and won't have to ask Casey about it."

"But you said..."

"You would know if somebody jabbed a needle in your ass," Voight said plainly, "maybe he was willing to go along with that, for whatever reason...but you think he'd agree to be a guinea pig to this extent for whatever Gabby had planned? Man loves his job, he would have to know he was a time bomb with two dozen drugs in his system, I don't think he'd really risk that if he knew."

"But why would he agree to any of it?" Kelly asked.

"Man loved his wife," Voight pointed out. "Me, he had no problem saying go to hell to, but Gabby? I don't see it. I think he was for the most part willing to go along with whatever she said, if for no other reason than to keep the peace. You do that in a marriage, you wouldn't know anything about that."

Kelly glared at him, but let it go. "It still doesn't make any sense. This is not Gabby."

"Not the Gabby you knew...I told you there were things about her you didn't know," Voight reminded him. "And this could just be the tip of the iceberg."

"Why would Gabby jeopardize him, and everybody else on the job like that?" Kelly asked.

"My guess, she probably dosed him the first day after each shift, then he had 24 hours to come down off what she gave him and act normal again before the next shift."

"But she had to know that it was still putting him and everyone else at risk," Kelly said.

"She knew he could die from a reaction to any one of the drugs that were in his system, all of them together...if she wasn't actively trying to kill him, it's anybody's guess what she was doing," Voight told him.

Kelly shook his head. "It just can't be right...Gabby wouldn't..."

"Look, Kelly, I'm a cop and I've seen stuff like this before, not usually to this extent, but I have seen it," Voight said. "Probably more than you have. Most of the time, it was somebody in the family who everybody swore could never do such a thing. Wives with their husbands, mothers with their kids, it's not unheard of."

"But why?" Kelly asked. "Why would she do it? What did she gain by it?"

"I can guess...how long were those two together? Three years? And all of a sudden she just starts doping him?" Voight shook his head. "Doesn't add up."

"That's what I've been telling you!" Kelly replied, clearly frustrated by everything that was going on.

"Was Gabby ever on any medications you know of? After the baby she lost, anything like that?" Voight asked.

"I don't know, why?"

"Because maybe she started drugging Casey early on into the relationship, and he just didn't know it," Voight said, and before Kelly could refute that idea, he added, "if he seemed just slightly off his game, that could've been attributed to his skull fracture, right? Nobody would ask too many questions about that."

"But why?" Kelly asked again, not sure anymore which end was even up.

"I'm not sure," Voight answered, "seems like something's missing."

"Like what?"

"Come on, I want you to see the bathroom for yourself."

Severide followed Voight across the apartment and he took in the splintered doorframe and spent a couple minutes examining it.

"Well?" Voight asked.

"This still doesn't make any sense," Kelly shook his head. "Casey didn't want Gabby filming him, so he locked the door to keep her out, and she kicked it in? Why?"

"We didn't find any drugs in here, or the bedroom," Voight told him. "All the same it's probably worth another look."

The two men headed to the bedroom and Severide looked through the drawers to the dresser and the nightstand, this time he didn't turn up anything.

"The drugs in the kitchen must be all there are," he said.

"That's already enough to kill a small army," Voight pointed out.

Kelly straightened his spine and looked in the mirror on top of the dresser, and he noticed something.

"Hey," he said as he reached behind the mirror and pulled out a smartphone.

"I thought you said you had both their phones," Kelly said.

"We do," Voight answered as he stepped over to the dresser.

Kelly looked at the phone in his hand and asked, "Then whose is this?"

"Let me see it," Voight took it from him. "Looks like Gabby had two phones."

"What for?"

Voight searched through it and his eyebrows raised, "Uh oh, looks like another video."

"Now what?" Kelly asked as he looked over Voight's shoulder.

Voight played the video, and the same shaky handheld view panned around to very familiar yellow tiling.

"That's the shower at 51," Kelly said.

He and Voight watched in silence as the camera zoomed in on one stall in particular that was currently in use. Gabby's hand reached out and yanked the curtain back, and Casey jerked around to see what was going on.

"Gabby! What're you doing here?"

"It's a coed locker room, I can be here if I want to be."

"You can't be in here, someone could come in."

"Then move over and close the curtain."

"No."

"Oh come on, Matt, you never want to do anything fun anymore."

"Gabby, get out, and turn that off!"

"No."

Casey's eyes widened. "What?"

"I said no." Gabby's voice had shifted from lighthearted and teasing to firm and hard. "I can do whatever I want, you are mine, you don't say no to me, Matt Casey, you will regret it."

"Gabby, I don't have time for this."

"You will-"

"Those bells can go off any second and you know that, now get out before somebody comes in."

Kelly's head felt like it was spinning. Even seeing it with his own eyes he couldn't bring himself to acknowledge what he was seeing.

"I don't get it," he told Voight, "obviously she didn't get what she came for, so why keep the video?"

Voight closed it and told Severide, "There's a lot of videos on here."

"What?" Kelly looked at the screen. "Are they all like that?"

"I don't know," Voight said as he shook his head.

"What's this one?" Kelly pressed the screen and started the next one.

The picture was darker in this video and it took a few seconds for Severide to realize this one was filmed right there in the bedroom. He could just barely make out Casey laying in the bed, seemingly asleep, and heard Gabby's voice before she actually came into the shot.

"Matt. Ma-a-a-tt."

"What?" Casey tiredly grumbled.

"You know what I want."

Casey grunted something and turned over, facing away from her and the camera.

"Matt," she said again, more firmly this time.

"No, Gabby."

"What do you mean no?"

"I don't want to, I'm tired, I want to get some sleep," Casey answered as he rolled back over to face her.

There was silence on the screen for a few seconds, a shadow covered Casey and it was hard to see much of anything, but the explosive sound of the slap was unmistakable, as was Casey's groan of pain.

"You don't ever say no to me, Matt Casey, you are mine, you got that?"

Casey's hands were covering his face, only half muffling the groan that was escaping him.

"Do you understand me?" Gabby's voice demanded to know.

"Ohhhh...yes," Casey reluctantly conceded.

There was a pause, then Gabby's voice dropped and became more ominous.

"If you don't want everyone to know, you'll do what I say, are we clear?"

The defeat in Matt's voice was clearly audible as he hesitantly responded, "Yes."

"Yes what?"

"Yes...Gabby."

"Good. Now turn over."

"Gabby..."

"Turn...over," her voice responded slowly and threateningly.

Casey sighed as he obeyed her. Gabby came into view now as she pulled down the covers, and Voight and Severide just barely saw the syringe as she stuck him with it. A stifled moan escaped Casey.

Gabby exhaled satisfactorily and said, "Just give that a few minutes to work and we'll be ready."

"Gabby," Casey turned back over and asked her, "Why are you doing this?" He sounded near tears as he asked her, "Why are you doing this to me? I love you."

Gabby's voice took on a tone that turned Kelly's spine to ice as she responded, "I know, and you're going to prove how much you do."

The picture was too dark to make out much aside from outlines and a few movements, but after a couple minutes the only sounds on the video were the pained, reluctant moans from Casey that bordered on screaming, and the louder, more consenting and obscene noises Gabby was making. Kelly turned and ran out of the bedroom and just made it to the bathroom as he started to violently throw up.

Kelly didn't have any idea how much time had passed. He didn't know when he'd finally stopped throwing up. When he finally had, he didn't have the strength to get back on his feet and he just sat with his knees bent and his back leaned against the cabinet under the sink. He was aware of the tears that continued to run down his face but he felt all but physically numbed to them by now, he couldn't even remember when he'd started crying, or why exactly. The world as he'd known it ceased to exist, nothing made sense anymore. He balled one hand up and ran the knuckles across his cheek and streaked the tears away, it didn't seem to matter, a few minutes later there was a fresh batch to replace them.

Finally Kelly decided he couldn't hide out there anymore and reluctantly got to his feet and opened the door.

Voight was waiting for him outside.

"You alright?" he asked. Kelly was surprised by what seemed to be genuine concern.

Kelly absently raised a hand to his mouth and squeezed his eyes shut as he worked his way up to explaining, "A few weeks back, Casey started showing up on shift...and I could tell he hadn't showered. He always had an excuse, the water heater was broken, he didn't have time...I didn't pay much attention to it. Then I started noticing...the only time he'd go to the locker room to shower or change, was when Ambo was out on a call...we'd come back from calls, he'd be caked in soot and ash, soaking wet, stinking to high heaven, but he always had an excuse something he had to get done first. I wondered, but I never asked, I decided it was none of my business...figured whatever he was going through, he'd deal with. I didn't know...I had no idea..."

"Kelly, he didn't want you to know, you or anyone else," Voight told him.

And that was the only thing that could hurt him worse than what he'd just witnessed.

"Why didn't he tell me?" Kelly asked helplessly. "Why didn't he tell me what was going on?"

"Kelly, he couldn't tell anyone about this," Voight pointed out.

Kelly's head was swimming and his knees felt like jelly, he just about hit the floor when Voight caught him.

"Easy," he said as he eased the Squad lieutenant onto the carpet. "Easy."

"You...did you know?" Kelly asked, just about on the verge of hysterics.

"I suspected something was up," Voight told him. "I understand shock, but I also know how you guys work. I was on the scene right after Gabby was shot, and I couldn't figure out why Casey wouldn't go near her, wouldn't even try to resuscitate her...he must've been so scared that she was still alive, and so relieved when he found out she was dead."

"Oh God," Kelly groaned as he felt his eyes burning. "This is a nightmare."

"I know."

"What now?" Kelly asked as he felt tears streaming down his face again, "Everybody thinks that Gabby...that they were...nobody knows, everybody's waiting to...everybody's going to be sending sympathy cards, flowers, God, how cruel can it be?"

Voight shook his head, "Kelly, you can't tell them about this, it's not your place to do that."

"Casey's not going to tell them, they have to know..."

Voight shook his head again. "Casey didn't want them to know, and only he can decide when and if they do find out. Obviously Gabby was blackmailing him with something, and what we have to do is find out what it was."

Kelly looked at the Intelligence sergeant with wide eyes void of any hope and asked, "What could she possibly blackmail him with?"

"You let me figure that out," Voight told him as he grabbed Kelly under the armpits and pulled him to his feet. "What you've got to do is be there for your friend now, he needs somebody and you're the only one he can trust."

"How do I tell him that I know about this?" Kelly asked.

"I don't think you'll have to."

"What?" Kelly thought back to last night, "Oh my God."

In between sobs he choked out, "Kelly...do you know...do you know..." that was as far as he could get.

Kelly thought Matt had been asking about who killed Gabby. Now he realized what Casey was really trying to ask, but was still too scared to find out the truth.

"That's why he didn't want me to leave him this morning," Kelly realized. "Because I didn't know, and he was worried I'd find out."

"I'm sure you can appreciate how hard it is for him right now," Voight said. "If you want to be there for him you have to realize what we're working with. You can't push him to talk about anything that's happened, he's still got enough drugs in his system his head isn't in the right place yet, we'll have to wait until he's good and sober to question him about anything and even then there's a good chance he won't tell us anything. You want to help him, you're going to have to let him come to you, and you're going to have to have more patience with him than you ever did before. His wife's been drugging him, raped him, she's dead and everyone around him still thinks she was a good person, and again, there's a good chance he doesn't realize the extent of what she did to him. Only time will tell how much he really knows, and whether he does or not, he's going to have to decide to tell you about it, and if he doesn't, you have to accept that and leave it be. Got it?"

Kelly slowly nodded.

"Okay," Voight said, "You need to make sure 51 stays in the dark on this one, I'm going to call in my crew and we're going to bag all the drugs, and have our tech guys go through her phone and see what all they find. We need to know what Casey was dealing with."

"But what good will that do? Gabby's dead."

"We have to find out what she was blackmailing him about, depending on what it was, we could still be looking at an open investigation with other perps involved. Gabby got her hands on a lot of drugs that shouldn't have been able to leave the ambulance or the hospital without somebody paying better attention, maybe she was getting them off the street or from another ambulance company, if so we have to find out who she was working with. In any case, Matt Casey is going to need professional help to get past this, and the doctor is going to have to know everything he can about the case, even the stuff Casey won't or can't fill him in on," Voight explained.

Kelly hated to admit it but he knew the sergeant had a point.

"I need to...I need to..." Kelly stepped away and looked around the room, "I need to get him a change of clothes to take back to the hospital..."

"Kelly..."

"Yeah, I know, I won't blow it," Kelly sniped.

"I was going to say you might look into talking to somebody too," Voight told him. "Gabby betrayed everyone, this isn't something even you can just walk away from."

"I'm..." Kelly let that lie die on his lips, he couldn't even pretend he was fine. "I have to get back and see how Casey's doing."