"I bet you wouldn't care if Derek did it!" Luke spat across the room towards Penelope's retreating figure in the doorway.

She stopped in her tracks and her breath caught in her throat. That hurt more than she would've thought it might, and it was also completely and entirely out of left field - like, she wasn't even wearing her baseball glove for that one, and she had no idea how to field it. Her relationship with Derek had always been off-limits to Luke, an unspoken rule that they'd both followed religiously from the second Agent Alvez stepped foot into the BAU for the first time right up until this moment, standing in Penelope's bedroom in their pajamas, a mix of both their tee-shirts in the washing machine and each of their toothbrushes side by side on the bathroom counter.

"What did you say?" She turned around slowly, her voice soft, trying to give Luke an out, a chance to change his mind or back down. She should've known better though, than to think he'd backtrack. It just wasn't his style. He didn't back down when bad guys seemed impossible to find or when his Unit Chief gave him an order he found unfair or when the cute but snappy technical analyst at his new job absolutely refused to so much as smile in his direction; he certainly wasn't going to back down now.

"I said I bet you wouldn't care if Derek Morgan left his socks on the floor!" He reiterated, and Penelope found herself almost laughing at the absurdity of it all. They'd been arguing about nothing and everything all day, and her snide comment about Luke's dirty socks on the floor of her bedroom had been, apparently, the last straw. A part of her wanted nothing more than to laugh a little, cry a little, and curl up in his arms to watch some dumb comedy before they fell asleep - but backing down from a fight wasn't her style, either.

"How dare you," she growled lowly. "You don't know anything about Derek Morgan." Her fists clenched, her teeth barred, and she could practically feel the steam seeping out of her ears. Though her body stood almost perfectly still, her mind and her heart raced back two years, and suddenly Luke wasn't the man she loved but the new agent she couldn't stand, the guy replacing the man whom she'd been sure was the love of her life.

"I know he's in love with you!" Luke's hands flew into the air as the words rushed from his lips. He was nearly shouting now.

Penelope felt a scream rising violently in her throat and fought to suppress it in her chest. "God, would you people stop saying that?" She stomped her bare foot furiously to punctuate her words her hands flew to her head, running through her hair over and over again with frantic energy. "Everybody wants to romanticize Derek and me, but you're all seeing things that were never there! Stop trying to protect me from the truth: I spent the better part of a decade pining after him, and he wouldn't have wanted me if I was the last woman on earth!"

A deafening silence rang through the apartment. Penelope wanted to crawl into bed alone and cry. She wanted to wake up tomorrow and forget this day ever happened, forget this argument, forget that Luke had ever seen her cry or heard her yell. She wanted to forget that she'd loved Derek and that she'd lost Derek and that she'd loved Luke and that she was, she was sure, about to lose him, too.

"You're wrong," Luke said quietly, his voice heavy with an emotion Penelope couldn't identify. "He loved you, Penelope. Still does."

Penelope sighed and threw up her hands. "What does it matter, anyway? Even if you were right, which you're not, he chose Savannah. He's gone, and I'm still here." She paused, looking hesitantly towards Luke. "And you're here. And this feels right - most of the time."

Luke suppressed a laugh at her honesty, his mirth mostly dissipated after Penelope's outburst.

"Yeah, I loved Derek," She said almost flippantly, and she marveled to herself at how easy it finally was to admit after years of denying it to anyone who got anywhere near the topic. "But he's got Savannah, and Hank, and his own life now. I've moved on." Though she'd said those words before, she meant it this time. Her heart was no longer tied to Morgan the way it had once been, and she had let go of her regrets about what might've been in another timeline.

She took a few tentative steps forward and took Luke's hands gently in her own, slowly, giving him the chance to pull away. He didn't.

"And I have you," She finally said. "And yeah, some things about you are a lot like Derek. You're both smart, you're both gorgeous-" Luke couldn't decide whether to feel proud or jealous; he decided to focus on the fact that she found him so attractive and found himself grinning in spite of it all - "You both have tempers that get the best of you sometimes." Penelope

gave him a pointed look, and he knew they were both remembering the night not too many months ago that found him chasing down an UNSUB in contradiction of Emily's orders, blinding by his rage and his burning need for justice.

"But you're so many things that he wasn't, Luke," She continued. "You're kind and forgiving and thoughtful in a way that Derek never was. Honestly, I don't know if you're my forever." She confessed. "I've been down that road too many times before to get caught up in promises again. But I want you to be my today. And I want you to be my tomorrow. And I want you to be exactly who you are." She paused, looked over her shoulder, and added, before leaning in for a kiss, "But a version of you who puts his socks in the damn hamper."