A clap of thunder shook the house, the sky groaning loudly as the ominous sound seemed to draw closer and closer by the minute. Bolts of purple lightning electrified the black sky while rain hammered down on the streets below, gale force winds creaking the windows and doors.

Esté was sat in Tony's bedroom with her hands over her ears and her knees pulled up to her chest, eyes squeezed closed. They were nine years old at the time and Tony had just gone downstairs to ask his mother for some more popcorn, leaving Estélla by herself.

She wasn't afraid of the rain or the dark, but the rolling thunder made her jump out of her skin each time, shaking her to her core the same way it did the house.

The hot summers often drew in heavy storms and that night was no exception. Estélla and Tony had been playing in Central Park all day and had convinced their parents to let them have a sleepover once dinner was over with.

They demolished an entire bucket of popcorn thirty minutes into the movie Maria had put on for them to watch after they'd changed into their pyjamas and the thunder didn't seem so loud when the television was on. Now the movie was paused though, Estélla could hear everything.

She yelped when the thunder cracked again, this time feeling like it was right outside of Tony's bedroom window, like it couldn't possibly get any closer if it tried. Esté was shaking with her hands still over her ears, lips trembling as some tears crept from the corners of her closed eyes.

"I got the popco- are you alright?"

Tony left the popcorn on his bedside table and crawled up beside her, peering at her face and giving her a gentle nudge to open her eyes. He didn't like seeing her cry, but it was clear that his best friend wasn't upset, she was just scared.

"I don't like the thunder," Esté said quietly, shaking her head.

Tony grabbed the blanket and draped it around their small shoulders, wrapping his arms around the girl and holding her against his chest, her face buried in his shoulder.

"It's okay," he said gently, giving her a reassuring squeeze, "It can't hurt you."

She sniffled beneath the blanket and looked up at him with her big blue eyes, "Please don't leave me again, Tony."

"I won't," he shook his head, "I won't ever leave you. You're safe. Don't worry, Stella."

Tony leapt out of bed when the second rumble shook the walls of the hotel room. Esté pulled the cold covers up over her body and watched as he stared out at the city below them.

She had no idea what it was that Tony was looking at, but she noticed the way his knuckles turned white and his body stiffened, a different type of tension now filling the room all of a sudden.

"Tony?" She said nervously.

He stayed still for another minute before turning around and immediately pulling on his clothes, saying nothing while he did so as he tried to collect his thoughts.

Tony had seen a lot of things in his life that he almost still didn't believe were real had he not still got the scars and the stories, but watching as some kind of spaceship descended down onto Tower Bridge was towards the top of his list of the absurd and terrifying.

"I have to go."

"No," Esté shook her head.

Tony recognised the fear in her eyes. The horrific sounds of buildings collapsing and people's screams from outside had pushed an inconsolable panic into her.

He swallowed and sat beside her on the bed, pulling her body into his own and holding her there, head pressed against his chest while he breathed in her scent with his eyes closed. She clung to him like a child, the unknown of what was happening outside shaking her to her core and jolting her bones whenever another crash echoed through the streets.

"I have to," he said calmly, though inside Tony felt anything but, "You need to stay here. I will come back for you."

She shook her head again, tears pooling in her eyes as her bottom lip trembled, "Please don't go, I'm scared."

Her words cut his heart into pieces, feeling cruelly guilty for abandoning her when it was so glaringly obvious that all she wanted was his comfort, his sanctuary and his safety that she couldn't find anywhere else. He knew that because he felt that way too, never having a mind as quiet and at peace as he did when he was with her, all his worries seeming meaningless whenever she touched him or said his name.

Still, he had a job to do, and considering he was on an entirely different continent to the rest of the team, he had to do it alone.

Estélla had been afraid before. She'd been afraid of jumping into the deep end of her swimming pool and diving off the edge of a boat into the Mediterranean Sea. She'd been scared of competing in her gymnastics competition in school and she'd been scared of the thunder and lightning that turned the blue skies she loved a frighteningly dark shade of black.

But Tony had always been there. He'd held her hand and he'd covered her face with a hug, soothing her and protecting her until the bad things went away. She trusted him and she put her safety in his hands, her soul in his strength and willingness to guard the thing he loved most in the world.

"I'm sorry, sweetheart," Tony choked out, feeling his eyes grow wet from the lump in his throat, "Please stay here, but if you can't, I will find you."

He took off the silver chain from around his neck and clasped it against her skin, letting it lay loosely at her collarbones.

"Don't take this off," he said firmly, holding her face in his hands, "Nothing will hurt you and nothing bad is going to happen, I promise."

Estélla knew that Tony had no choice but to leave. She'd never been anything close to a selfish person but in that moment she didn't care about the rest of the world, she just wanted him to stay. She wanted him to wrap her up in his arms and to cover her ears with his hands until the noises stopped and the sun rose again, but as the looming shadows crept across the window, she knew that time was running out.

He brushed his thumbs across her tear stained cheeks, glancing between her hopelessly drowned eyes and pouted lips. The sight hurt him, twisting the knife that was wedged in his chest and scalding his veins with a release of predetermined regret.

"Be careful," she whispered, accepting that there was nothing she could do or say to change his mind, "Please, please be careful, Tony."

The thought of him not coming back to her like he promised was too dark to linger on and Esté immediately dismissed the possibility altogether. She still had a hard time trusting Tony deep down, but she believed him then when he said that everything would be okay, and she believed him when he told her that he loved her, too.

"I will," he nodded quickly before kissing her lips.

It was perhaps the most desperate kiss they'd both ever shared, a dangerous suggestion that it could be their last making it almost impossible to pull away from the taste they craved like oxygen, the warmth and the safety they found in something so simple.

"I love you, Tony."

He sighed heartbreakingly as he finally broke the kiss, standing up and looking down at Estélla with a twist in his gut that made him almost crumble and drop back beside her, aching to crawl beneath the covers and hide from the rest of the world.

Tony didn't care if bridges fell and cities burned, not really, not when it came at the price of leaving Esté. He couldn't live without her, at least not the way he wanted to, remembering how his judgement and his life fell apart after she turned her back on him and how it all seemed to fall back into place when he kissed her again. Tony couldn't live without her, he wouldn't, and he had to fight every urge in his soul to walk away from her that night when everything inside of him was screaming at him telling him to stay.

He stood there with heavy limbs and a racing mind, placing one hand over his heart as he stared at her with love pouring from his dark eyes and through his quiet whisper of sacred words.

"I love you, Stella."

He believed his own voice just as faithfully as Estélla did, but when Tony ran out of the hotel after wiping tears from his face and covering himself in red and gold, he was faced with the heavy realisation that he shouldn't make promises that he couldn't keep.