"Steve," she whispered into the phone one night. "I know it's late but I...can you come over?"
"...Christina..." he said skeptically. Christina blushed.
"No no, not for...I just...Tony and Pepper are out at some function or another, and it's really creepy being here alone and..." Steve could hear her teether chattering through the phone. "...please can you just come?"
There was silence.
"Steve? Steve!"
"Christina?"
"Yeah?"
"Open your door."
Christina gasped and thew open her bedroom door, throwing herself into his arms.
"Christina, you're shaking," said Steve, wrapping his arms around her.
"I'm cold," she lied, burrowing her face in his shirt.
Steve smiled into her hair. "That might have something to do with the fact that you're wearing shorts."
"What, you don't like them?" Christina giggled. Steve rolled his eyes, then scooped her up.
"Steve!" she gasped. "What are you doing?"
"Didn't you say you were hopelessly romantic?" he replied. "I think this qualifies."
"Oh, absolutely. But you should know that now I'm not letting go of you," she said as he attempted to lay her down on the bed.
"Oh really?"
"Mhm." She nodded and pressed her lips to his, pulling him on to the bed with her.
He pulled away, smiling, and tapped her nose. "You have to go to sleep."
She pouted. "But now you're here."
"Come on..."
"Fineee..." She slid between the sheets, while he stayed above the covers. She snuggled into him, clinging to his shirt. "I need you to do something for me..."
"What is it?" he asked.
"...Stay with me while I sleep..." she murmured. "Hold me tight..."
He wrapped his arms around her tightly and murmured, "What are you scared of...?"
She shut her eyes tightly and mumbled. "The nightmares."
"Nightmares?"
She nodded slowly. "I have these awful nightmares...like thrashing and twisting the sheets and screaming and getting no sleep nightmares. Sometimes I don't sleep, just have nightmares. Sometimes I do neither, just float in and out on consciousness. Monsters come out in the dark, Steve, don't you know?"
He held her tighter. "I do know," he said softly. "But what monsters could possibly be chasing after you?"
She wrapped her arms around his torso. "Monsters that are good at hiding." She took a deep breath and looked up at him. "I need you...to hold me when they come."
Steve nodded and kissed her forehead. "I promise."
She smiled, murmured "goodnight" and snuggled into him.
It didn't take long for the terrors to start. She would cry and toss and turn and whimper and mumble unintelligibly, and the whole time, Steve held her.
He didn't even hear that they were home until he heard Tony open the door quietly.
"Tony-"
"Get the hell out of my sister's room, Rogers. Christina-"
"She's sleeping!" Steve hissed.
Tony was exasperated. "What the hell are you doing-"
"She asked me to-"
"She asked you?"
"Yes, she-"
"Why?"
"Because of her nightmares!" Steve whisper-shouted. Tony paled.
"She...has nightmares?" he asked. Steve nodded.
"She asked me to come over so she wouldn't be alone, okay? She made it absolutely clear that that was the only reason. When I got here, she...she asked me to hold her when the monsters came for her."
Tony was quiet. "This is the first you've heard about this...?"
Steve nodded. "She told me she had trouble sleeping, but...she never told me it was this bad. She keeps crying..."
"Crying?"
"Yeah..."
Christina shifted in her sleep and whimpered. "T-tony..." she mumbled. "Steve...no..." Steve got to her first.
"Shh, baby...it's okay...I'm here..." he murmured, stroking her hair. Tony sat at the edge of the bed, watching curiously.
"...I know you want to kill me for being here," said Steve, "But I couldn't just...say no to her."
"You could've."
"No, I couldn't."
"Why?"
"...Because I'm falling for her."
Tony stared at him, dumbfounded.
"...I know you don't approve of us, and I didn't expect you to..." said Steve softly. "But don't think for a second that I'd let Loki or anyone else hurt her."
Tony looked at him seriously. "Let's get one thing straight Rogers. You treat her right, make her happy, it's fine by me. But if you hurt her in any way, shape, or form, I will kill you, very slowly."
Steve nodded just as seriously. "I won't hurt her. I promise."
Tony looked from him to his sister. "I'll hold you to that, Rogers. You can go now...I'll take it from here."
Steve shook his head. "I promised her I'd stay."
"Steve. Please. Go. Now."
There was something about Tony Stark calling him "Steve" and not some joke about "Captain" or just "Rogers" that told him he was serious, so he simply nodded and left.