The Billionaire's Heir I Never Knew Was Mine

Zachary raised one brow slightly but didn’t question her further.

The elevator ride up felt absurdly fast.

Sienna stood beside Zachary in the small elevator, gripping her bag tightly as she tried not to show how his warm presence, just inches away, made her heart race with excitement.

Unfortunately, that was impossible.

The quiet scent of his cologne lingered around her, clean and subtle, making her increasingly conscious of every little movement.

Meanwhile, Zachary stood calmly beside her with both hands in his pockets, looking completely relaxed.

"How can you be so calm?" Sienna suddenly blurted out without thinking.

Zachary turned slightly toward her. "About what?"

"This," she said vaguely, gesturing around them. "You’re going to a woman’s apartment at night, and you look completely normal."

His expression remained calm.

"Should I panic?"

"Yes. At least a little."

To her surprise, Zachary chuckled softly again. "I trust you."

His answer instantly left Sienna unable to say anything more. Her heart, already struggling all night, finally gave up trying to behave normally.

’What kind of answer is that? Trust me? I would be the one who said that, right?’

She was speechless, unable to say a word. Thankfully, before she could embarrass herself further, the elevator doors opened on the tenth floor.

Sienna walked out first, trying to regain her composure while leading him down the hallway toward her apartment.

The closer they got to her door, the louder her heartbeat became.

Finally, they stopped in front of her apartment.

Sienna quickly turned toward him.

"Zach," she said hurriedly while trying to calm her chaotic heartbeat, "wait here for a moment. I need to check something."

Zachary blinked once, clearly confused.

"...Check what?"

But Sienna had already unlocked the door.

"Won’t be long..." she answered nervously before slipping inside and immediately shutting the door behind her.

Silence.

Zachary stood alone in the hallway, staring at the closed door with a puzzled expression.

Inside the apartment, chaos began immediately, at least in Sienna’s mind.

She dropped her bag onto the sofa and looked around in a rush.

"...Okay, calm down, girl... Take a deep breath..." she whispered to herself. "Focus and put your mind into it! And please don’t embarrass yourself tonight."

Her eyes moved quickly around the living room, just to make sure everything was in place. Thankfully, it was relatively clean.

Then she noticed a blanket thrown carelessly over the chair. She rushed forward and folded it.

She spotted a mug on the table. In a flash, she rushed over to put it in the dishwasher.

Then she froze again when something crossed her mind, her eyes fixed on the fridge.

"Oh, right, food. Did I have anything left there?"

Sienna rushed to the refrigerator and opened it. She noticed it was almost empty because she had only planned to go shopping tomorrow morning.

She could only find eggs, a few vegetables, half a pack of dumplings, and instant pizza.

"Can he eat food like this?"

She stood before her open fridge in silence, regretting her decision to accept his offer.

"...This is either a meal," she muttered, "or a crime, Sienna."

...

Outside the apartment, Zachary remained standing quietly in the hallway, his shoulder resting lightly against the wall beside the glass wall overlooking the city below.

The lights from distant buildings stretched endlessly into the night, glowing softly beneath the dark sky. At the same time, the quiet atmosphere around him settled into an unusual kind of calm.

And strangely enough, he found himself smiling faintly.

Zachary lowered his gaze briefly and exhaled through his nose, almost amused with himself.

’What exactly are you doing, Zach?’

For the first time in years, his own thoughts began criticizing him without mercy.

He had spent most of his adult life being rational. Careful. Controlled. Even when people around him acted recklessly, he remained the calm one in the room. The one who knew boundaries. The one who understood patience.

Yet tonight, he had somehow abandoned all of that.

’Since when do you do things like this?’

His eyes drifted toward Sienna’s apartment door.

He was supposed to see her tomorrow. That had been the plan.

Instead, he had offered to drive her home, followed her upstairs, and now stood outside her apartment, past ten o’clock at night, waiting for her to invite him inside.

The situation itself sounded absurd when he thought about it carefully.

’Have you completely lost your mind?’

A quiet sigh escaped him.

Unfortunately, the voice inside his head continued.

’Or are you pretending not to notice why you came here?’

Zachary rubbed lightly at his temple before shaking his head once, as if physically trying to silence his own thoughts.

It did not work. Because the truth was annoyingly obvious. He wanted to see her. That was all.

And somehow, that simple fact alone had already pushed him far beyond the limits of his usual behavior.

’You are shameless, man.’

The sound of the apartment door opening beside him interrupted his thoughts immediately.

Zachary turned toward the door and found Sienna standing there, holding it open, with warm light spilling softly behind her. Her expression remained composed, though he noticed the slight caution in her eyes almost instantly.

"Everything alright?" he asked casually, keeping his voice calm despite the strange tension tightening quietly inside his chest.

"Hmm." She nodded lightly. "You can come in."

He noticed it immediately afterward... She was nervous, not awkward in an immature way. He could clearly see that Sienna still carried herself naturally, still spoke calmly, and still tried to maintain composure.

But he could see the subtle signs. There was a slight stiffness in her shoulders. The careful way she held her gaze for only a few seconds at a time before looking away, trying to be discreet.

He stepped closer but did not enter immediately. Instead, his gaze moved briefly past her shoulder toward the apartment interior before he spoke again.

"Did you hide someone inside?"

The question was a joke intended to lighten the mood between them.

Unfortunately, it only startled her.

Her eyes widened at once in utter shock. "Wh-What?"