Bulletproof Until You

1

The bullpen was louder than usual-phones ringing, chairs scraping, voices overlapping-but it all faded the second the elevator doors opened.

Jay Halstead stepped out first, already mid-sentence.

"I'm just saying, you could've at least warned me-"

"-warned you?" Mackenzie Halstead stepped out right behind him, bumping his shoulder as she passed. "You're the one who told me to 'keep you in the loop.' This is the loop."

Jay scoffed, dragging a hand over his face. "Yeah, not this loop. Not you showing up unannounced to work in my unit."

Mac smirked, adjusting the strap of her bag. "Relax, big brother. You survived me growing up, you'll survive me now."

From across the room, Kim Burgess leaned slightly toward Adam Ruzek. "Please tell me that's who I think it is."

Ruzek grinned. "If it is, this just got way more interesting."

Jay kept going, lowering his voice but not enough. "You didn't think maybe-just maybe-I'd want a heads-up before my little sister becomes my coworker?"

Mac stopped walking, turning to face him fully. "First of all, don't call me 'little sister' in front of your team. Second, you don't get to pull rank here, Jay."

"I'm not pulling rank."

"You're absolutely pulling rank."

"I'm just saying-"

"You're saying a lot of things, actually."

Kevin Atwater leaned back in his chair, watching the exchange with a slow grin. "Yo... I'm already entertained."

Hailey Upton crossed her arms, amused. "We should grab popcorn."

Before Jay could fire back, Hank Voight's office door opened.

"That enough?" Voight's voice cut through the room.

Jay straightened instantly. "Yeah. Sorry, boss."

Mac didn't miss a beat. "We're done."

Voight's eyes flicked between them, then landed on her. He gave a small nod. "Good. Because I don't have time for family drama. Halstead-" he pointed at her, "-you're up."

Jay opened his mouth. "Boss-"

Voight held up a hand. "Save it."

Mac shot Jay a look that screamed told you so and walked forward.

"Everyone," Voight said, stepping out into the bullpen, "this is Mackenzie Halstead. Goes by Mac. She's transferring in-FBI, CIA background."

Ruzek let out a low whistle. "Okay... no pressure."

Kim's eyes widened slightly, impressed.

Kevin sat up a little straighter.

Voight continued, "She'll be working with us, full time. And she's not here because of him." He jerked his chin toward Jay. "She's here because she's good."

Mac gave a small nod. "Appreciate that."

Jay muttered under his breath, "Still would've liked a call."

She didn't even look at him. "You're still talking."

A couple of the team members laughed quietly.

Voight glanced around. "Atwater."

Kevin stood. "Yeah?"

"You're with her."

There was a split second-just a flicker-before Kevin nodded. "Got it."

Mac turned toward him, walking over with calm confidence. Up close, Kevin caught the details-the stacked earrings, the sleeve of delicate floral ink, the sharpness in her eyes that didn't miss anything.

She stopped in front of him and held out her hand. "Mac."

Kevin shook it, firm but easy. "Atwater."

Her grip was solid. Grounded. Not trying to prove anything-but not something you'd underestimate either.

"Guess we're partners," she said.

"Looks like it."

Jay stepped closer, pointing between them. "Hey-just so we're clear-"

Mac didn't even turn. "No."

Kevin blinked. "No... what?"

Jay frowned. "No what?"

She finally looked at Jay, raising an eyebrow. "No speech. No 'be careful with her,' no 'she's my sister,' no weird big brother threats. We're not doing that."

Ruzek snorted. "Aw, come on, man, I was kinda hoping for that."

Kim nudged him. "Same."

Jay looked personally offended. "I wasn't gonna-"

"You were," Mac and Hailey said at the same time.

Kevin laughed under his breath. "I believe them."

Jay pointed at him. "Don't encourage her."

"Too late," Kevin said, shrugging.

Mac's lips twitched, just barely.

Voight clapped his hands once. "Alright, enough. We got work. Burgess, Ruzek-follow up on that robbery. Upton, Halstead-interviews. Atwater, Mac-you're with me."

"Copy," Kevin said.

Mac grabbed a file off the desk without hesitation, falling into step beside him like she'd been there for years.

As they walked, Kevin glanced at her. "So... Mac, huh?"

"Yeah."

"Not Halstead."

She shook her head. "Definitely not Halstead."

He smiled a little. "Got it."

Behind them, Jay called out, "I can still hear you, you know!"

Mac didn't even turn around. She just lifted her hand and flipped him off casually over her shoulder.

The bullpen erupted in laughter.

Kevin couldn't help it-he laughed too, shaking his head. "Yeah... this is gonna be fun."

Mac glanced at him, a spark of something warm breaking through her otherwise controlled expression.

"Yeah," she said. "It is."