Off Limits: My One-Night Stepbrother

chapter four:my stepbrother

_Ariana's POV_

The realization hit me like a slap.

Kian Mercer.

He was the guy from last night. The guy in the room whose shoulders I’d recognized, the guy whose voice had made my skin prickle. My stepbrother. The son and heir of Mercer, one of the richest multi-billionaires in New York.

I gasped before I could stop it.

For half a second I saw it on his face too—surprise, sharp and real. Then it was gone, replaced by that lazy smirk like he’d just solved a puzzle he didn’t care about.

“I’m guessing what you needed to forget,” he said, voice low and amused, “was the annoying stepbrother and father you’d have to meet today.”

He reached past me, close enough that his arm brushed mine, and grabbed an apple from the fruit bowl. The movement pulled his shirt tight across his shoulders, and I hated how I noticed how his muscles shifted under it. Hated it more that I didn’t look away fast enough.

He turned back to me, studying me like I was the inconvenience.

“Feel free to take a picture if you want,” he said, stepping closer. “Please. You’re not _that_ attractive.”

“Really?” He tilted his head, eyes dropping for a second before dragging back up to mine. “Because last time I checked, you asked me to sleep with you. I gave you a chance to walk out. You didn’t. I made you moan, remember?”

My face burned. I gulped, but nothing came out.

“I think it’s because I was very attractive,” he continued, voice dropping. “And you took my c**k well. Who knew you, beautiful little thing, would end up being my stepsister?”

He leaned in.

His mouth stopped a breath away from mine, close enough that I could feel the heat of him, smell the faint trace of soap and something darker. My pulse jumped before I realized I’d leaned forward too. His lips barely brushed mine—just a ghost of contact that made my stomach twist.

Then his phone buzzed.

He pulled back like it annoyed him more than it should, glancing at the screen.

“Welcome, little sister,” he murmured, the words carrying that edge that made my heart stutter in the worst way.

He shut the fridge door with one hand and walked out, leaving me standing there with juice drying on my shirt and his words still ringing in my ears.

I didn’t move for a full minute.

Flabbergasted didn’t even cover it.

And I thought things couldn’t get any worse than they already were.

I hurried to my room afterwards, still clutching the chips, wondering how of all people he was the stranger. In fact, he wasn’t a stranger anymore.

I had literally slept with my stepbrother.

Before the thoughts settled any deeper my phone rang. It was Mia.

“Are you aware of Sophie and Adrian? What the hell happened?”

I sank onto the edge of the bed and exhaled.

“He got bored of me and hit it off with Sophie. They both had an affair behind my back.”

“How did you find out?” she asked, voice sharp with disbelief.

“Check Adrian’s insta page.” She said immediately after, not waiting for me to answer the question.

I did. There was a video of him and Sophie. His hand across her chest, phone in the other hand — you know that mirror video stuff, that’s it. Then Sophie turned slightly to face him as he kissed her.

What I was… was more than furious. I was pained. He was showing her off to the world as if he didn’t just— just…

“Hey, are you still there? Are you okay?” Mia’s voice came through again.

“Yeah, I’ve seen it. And yes, I’m still here. But the ‘okay’ part is what I don’t know.”

“Everything will be fine. He didn’t deserve you.”

“Yeah… he didn’t.”

I told her how I was finally in my stepdad’s mansion. Mia and I were close. She was my next closest friend after Sophie, and she knew nearly everything about me.

I showed her around on video call and she was in awe.

“What about your stepbrother?”

“He’s here,” I said. I didn’t want to go further.

“Anyways, we’ll talk later when I’m done unpacking.”

Just like that we said goodbyes and I ended the call.

After the call ended, I went back to unpacking.

I’d only gotten halfway through when I realized my shirt was a mess—juice from earlier, crumbs from the chips, all of it. My clothes from the suitcase had gotten spilled across the bed too when I was moving too fast earlier.

I dumped the empty chip bag, grabbed some clean clothes, and changed fast.

Then I stopped in front of the mirror.

I looked normal. No one would guess that about an hour ago I’d found out I’d slept with my stepbrother, and that my ex was all over my best friend on i********:.

“Good,” I muttered to myself.

Before I could overthink it again, there was a soft knock.

“Miss, lunch will be served in five minutes,” a voice said from the hall. The butler.

I grabbed my hair tie, pulled my hair back in a messy knot, and finished shoving the last of my clothes into the drawer. Chips bag went in the bin. Shirt looked clean. That was enough.

I went downstairs.

The place smelled like food already—roast chicken, garlic butter, something sweet with cinnamon. My stomach twisted, but not from hunger.

Everyone was already sitting.

The dining table was massive, dark wood polished to a shine, stretching long enough for twelve people and only five of us using it. White plates, silver cutlery, crystal glasses. In the center were dishes scattered like it was a feast: roasted chicken glistening with herbs, mashed potatoes, grilled vegetables, a bowl of mixed salad, fresh bread in a woven basket, and a fruit platter with grapes, sliced mangoes, and berries. A small gravy boat sat next to a dish of cranberry sauce.

Mom was talking, animated as always, explaining something about the garden renovations to Mercer.

“And I told the landscaper, if he touches those roses again I’ll fire him myself,” she said, laughing.

Mercer nodded, cutting into his chicken with slow, deliberate movements. “You’re worse than my board meetings, babe.”

Kian was at the far end, phone in hand, thumb scrolling. He didn’t look up when I entered.

I took the empty seat next to Mom, across from Kian.

The moment I sat, Dad—Mercer—glanced up and smiled at me. Warm, practiced, the kind of smile meant to set a nervous new stepdaughter at ease.

I tried to return it. I hoped it didn’t look fake.

“Now that she’s here,” Mercer said turning towards Kian like he was about to make introductions.

“Kian, this is Ariana—”

Kian’s phone slipped from his fingers and clattered against the table, cutting him off.

“I know who she is,” Kian said smoothly, leaning back in his chair. His eyes lifted to mine, dark and too knowing. “Right, Ariana?”

“Right,” I answered, keeping my voice even. I forced a small nod, trying to stay cool.

“Ohhh, you guys have met already?” Mom asked, perking up.

I opened my mouth to cover it with something safe—_yes, we met earlier in the kitchen_—but Kian beat me to it.

“Yeah,” he said, that relaxed smirk tugging at his mouth. “I met her in the hotel I stayed in yesterday before returning today.”

“Ohhh,” Mom said, her eyes flicking to me, curious now.

I looked at Kian, hoping he wouldn’t say more.

“Yeah,” he added, voice low enough that only I really caught it. “We even talked, right Ariana?”

He was relaxed, one arm draped over the back of his chair, eyes locked on me like he was enjoying every second of this. Not a flicker of nerves. Just that slow, lazy stare that made it feel like we were the only two at the table.

“Yeah… right,” I muttered, dropping my gaze to my plate, refusing to meet his eyes.

Mercer chuckled, oblivious. “That’s nice. Small world. Glad you two got acquainted before today.”

“Let’s eat before the food gets cold,” he said, picking up his fork again.

Just like that, the table settled into a quiet lunch. Nothing but the sound of utensils against plates, the clink of glasses, the soft scrape of chairs.

I told myself not to look up. I failed.

My eyes drifted to him a few times. The way he cut his steak, slow and precise. The way his jaw shifted when he chewed. The way he didn’t even seem aware of how casual he looked doing it.

He caught me.

Kian set his cutlery down mid-bite, tilted his head, and quirked a brow at me.

It hit me instantly—same expression, same timing, as when I’d made a sound last night.

“Stop staring,” he said under his breath, just loud enough for me to hear.

My cheeks burned. I looked away so fast I nearly knocked over my glass.

Dinner ended shortly after.

Before anyone stood up, Mercer spoke again.

“Kian, your mum and I will be going out. Show Ariana around the house.”

Mom turned to me, softening her voice. “Ariana, if there’s anything at all you need, let me know, okay?”

Then she turned back to Kian.

“From now on she’s your sister. Treat her well. We’re all family now.”