"Erin, while you were sleeping on the plane, Rossi and I had a little chat. He and I both think that we need to talk with you and Blake, to figure out what about your shared past is causing the Replicator focus on the two of you. There's something that is just out of our sight, something important, and you and she are the keys to finding that missing link."

Erin sighed as she sat on the bed, looking up at him. There was deep resignation on her face, as if she had been expecting this moment for longer than he had known. "I was wondering when one of you were going to ask me about this. I have thoughts, but I don't know how accurate they'll be. But I don't want to involve Alex in this, not when we've worked so hard to be friends once more. There are secrets that we haven't told anyone, because…"

Derek felt like he knew what she was going to say, and he reached out to rest his hand on her shoulder, rubbing his thumb back and forth over her collarbone. "Because you think that we'll judge you, more than you've already been judged?"

Erin nodded as she pulled him down next to her. "There are things we did, things that we're not proud of. I know that it's in the past, but I still crave your good esteem." She leaned against him, resting her head on his shoulder as she began to quietly weep.

"Oh, Pretty Lady, you're going to break my heart. You need to realise that while the truth does have ways of hurting us, sometimes we feel better for the telling of it. So, when we get to the precinct, would you please talk with us? Just the four of, no one else needs to know what happened in the past, but we both feel that it might fill in the whole picture."

Erin sagged against him as she sighed. "Yes, fine, if Alex agrees to do so. I will not betray her confidences behind her back. I betrayed her once, I refuse to do that again."

"I will agree to abide by that, Erin. Now come, let's head in. JJ's waiting for us in the lobby."

Erin nodded as she awkwardly rose to her feet. "It would have been nice if this bed were a little higher. I think that I am going to need a week's worth of massages when we get back."

"And I will be more than willing to give them to you." He wrapped his arms around her waist before leaning down to kiss her forehead. "I love you, no matter what you tell me, nothing will change that fact of our lives. My love for you, your love for me, that won't change."

Erin choked back a sob as she nodded. "I do love you, darling." She leaned upwards and kissed his cheek tenderly. "All right, let's go before I lose my nerve and refuse to tell you anything."

He gave her a small smile before taking hold of her hand and guiding her to the elevators. They were quiet on the way down, as if she was thinking about what she would tell him about the past that she and Blake shared. JJ gave them a small wave before tossing the keys to him once they had reached her side. "You're not going to drive?"

"No, it's awkward enough to get in and out of the SUVs, and it's only going to get worse as the weeks wear on. And this will allow you to sit next to your wife?" She reached out and patted Erin's shoulder warmly. "We're going to need these bits of rest between the hunt for the Replicator."

"That is very true, Jennifer," Erin replied as they made their way to the waiting SUV. "How is your pregnancy going?"

"As easily as Henry's went. I don't want to jinx anything, but it feels good to know that there hasn't been much to worry about. And yours?"

"As easily as can be expected, if not a little better. I've finally put on some weight, like my doctor wanted. But I still want to take as much care as possible, and not end up on bedrest for the last three months."

"Oh, that would suck!" Erin nodded as she made herself comfortable in the seat, and then Derek was taking off for the precinct. Hotch met their vehicle and led them in, which was comforting to Derek, since he wasn't certain that he wanted any of them to be alone for a moment. Not when there was a madman on the loose, hunting them.

Once they were in the meeting room with the others, Derek looked around for Dave and Blake. They were in the corner, talking lowly to each other, and then she looked up, meeting his eyes. She gave him a small nod before Dave guided her out of the room. Derek immediately knew that he and Erin were to follow, and he looked at his wife, trying to give her an encouraging smile.

"That's our cue?" she asked, sounding nervous, and he nodded in response. "We'll join you three in a little while, Aaron. There's something that my husband and David feel needs to be discussed between the four of us before we reconvene." He was proud of the way that her voice betrayed nothing of what she felt, and then they were following after Dave and Blake.

"In here," Dave said, peeking his head out of an interrogation room. Derek nodded as he guided his wife into the room. "I thought it would be best if we did this where we'd be able to control who comes in and out of the room."

"Privacy is paramount for this discussion," Erin replied as she slipped free from Derek's arm and slipped past Dave. When he entered the room, closing the door behind him, Derek saw that Erin and Blake were huddled together in the furthest corner, darting occasional looks their way before whispering to each other once more. "All right, what we tell you does not leave this room, except what is absolutely necessary for the case. You two are going to learn more about us than we wanted known about a time where we both made mistakes. You will wait until we've reached the end to ask any questions, and unless they're focused on something important to the case, we will not answer them. I, I think you'll both understand once you've heard the story."

Erin took hold of Blake's hand and brought her over to the table, taking a seat with Blake. Rossi and Derek sat across from them, and it took everything in him not to reach across the table for his wife's hand. A part of him knew that that might make Erin shy away and refuse to talk, so he instead picked up the pad of paper and pen, knowing that he would have to take some sort of notes while they were talking. His wife gave him a brief smile.

"All right, Erin, Blake, what's so important that you couldn't tell everyone on our team?"

Blake cleared her throat and glanced at Erin before turning her attention on them once more. "I think that you've probably ascertained that Erin and I had had an intimate relationship in the past. It began when we were in the Academy together. For six heady months, we were the stereotypical roommates to lovers. Until my parents discovered what we were doing."

"They walked in on us, on a surprise visit. Damon was kind."

"That's because he always liked you. My mother was a different story. Anyway, I was introduced to James a few weeks later, and ended up pregnant two months later. What my mother didn't know is that James was understanding of what was between Erin and myself, and we still loved each other. She was maid of honor at my wedding, and I was matron of honor in hers, two years later.

"We both went on to get our PhDs before joining the BSU with Katie Cole. You were away in Paris by the time we joined, and then the Amerithrax case happened. I had hoped that we would be linked with Katie for that case, but ended up with John Curtis."

"He was difficult to work with, to say the least. Arrogant and self-serving, and it became all too easy to isolate ourselves in the bunker, in order to get away from him."

"Which eventually led to overnights in the bunker. It was easy to work out our frustration with the case in each other's arms. We were so selfish, our husbands didn't deserve what we were doing to them, especially since James had to watch Ethan so much, on top of working at the hospital. We thought that we were being circumspect, but as I look back on the situation now, I wonder how much John knew about what we were doing."

Erin nodded as she licked her lips absently. "I think he knew that we were sleeping together. At least James knew and somewhat understood. Alan knew nothing. He couldn't know anything, or…" Derek watched as Blake's hand tightened around Erin's, offering her comfort as she took a deep breath. "Anyway, as I was mulling over our shared past, to try and find something that would draw the Replicator's attention to us, and I have the sinking suspicion that John fed us that wrong linguistic profile in order to have us caught out. I don't think that he thought I would sacrifice my lover for my safety and job security." Erin drew in a deep breath before turning her head to look at Blake. "Alan, he, the night before we were pulled into the Director's office, it got physical, and he told me that if I told anyone, or stepped out of line, I would have nothing. I was scared, Lexie."

Derek unconsciously clenched his hands into tight fists, wishing that he could throttle Erin's ex-husband. Blake, for her part, looked devastated to have this new piece of the puzzle. As they watched, Blake drew Erin into a tight hug as she burst into tears. "So, Curtis was also collateral damage?"

"Yes," Blake murmured, still holding on to Erin. "He was so angry, too, that she saved her own skin. He tried to convince me to do something about the situation, but there was no will left in me at that moment to think about revenge. I just wanted to lick my wounds and forget that I had ever thought I loved Erin. Why?"

Derek knew the exact moment the penny dropped for Erin and Rossi, and both turned their heads to look at him. "No, darling," his wife whispered as she clung ever tighter to Blake.

"Yes. That is our missing piece. He's targeting you and Blake out of revenge. And since he's a former BAU agent, he's going to know almost all of our moves. And that also explains how he could know about our previous cases in order to copy them. And now, finally, we might be one step ahead of him. Because I doubt he would believe we would ever figure him out before he reached his endgame. He thinks that he has all the power, and now, we know that that's not true. Erin, we don't have to tell the others about your private affairs, just that this Curtis guy was also partners with you and nursed years of anger and hatred over being betrayed at the worst possible moment. That this is his revenge arc, and he will stop at nothing to ensure that you pay for what happened."

Erin blinked rapidly, as if she wanted to start crying once more. "Will you and David explain it to them, please? I need time to calm down, to wrap my mind around this theory of yours. I love you, so much, but this has to be done between Alex and myself. We won't do anything untoward, I just need…"

"I know, and it's okay. We'll come get you both in fifteen. Will that be long enough?"

"I hope so. Thank you," she whispered as Rossi got to his feet and left the room. Once the older man was gone, Derek went over to Erin's side and pressed a firm kiss to the top of her head before leaving the two women alone to heal and find an even keel after this revelation that their past was the exact thing that was causing so many people hurt.