The Undercover Heiress

A Deal with the Devil

Isa hadn’t known what suffocation felt like until now.

She sat rigidly at the long dining table, across from Adrian Costa, the man she was supposed to marry. Between them sat her father, Antonio Romano, and several of his most trusted men. The air was thick with tension, laced with the scent of expensive cigars and aged whiskey.

The engagement was official.

Or at least, that’s what everyone in this room believed.

Isa’s mind was still reeling from the conversation in her father’s study. She had agreed to this arrangement out of necessity, but that didn’t mean she would bow to Adrian Costa. The way he looked at her—calm, calculating, as if he already owned her—set her teeth on edge.

“So,” Adrian finally spoke, his voice smooth yet commanding, “how long do you plan on glaring at me, princess?”

Isa straightened her posture, forcing an impassive expression. “Until I wake up and realize this is all just a bad dream.”

A few of her father’s men chuckled, but Adrian’s expression remained unreadable. He leaned back in his chair, swirling the dark amber liquid in his glass.

“I’ll give you credit,” he mused, his lips curving into something resembling amusement. “Most people in your position would be smart enough to fear me.”

“I’m not most people,” she shot back.

His dark eyes glimmered with something she couldn’t quite place. Interest? Amusement? Annoyance?

“Clearly.”

Antonio cleared his throat, cutting into the tension. “Isabella, I understand this is a difficult situation, but it’s necessary. The Costa family is the only thing keeping us from being swallowed whole.”

Isa’s stomach twisted. She hated this. Hated that her father was right.

“I still don’t see how pretending to be engaged to him is the only way to fix this,” she said, arms crossed. “Why not a simple alliance?”

Adrian placed his glass down with a soft clink, his gaze locking onto hers. “Because your father’s enemies don’t respect words. They respect blood. Family ties.” He tilted his head slightly. “They won’t risk a war with the Romanos if they think you belong to me.”

Belong to him.

Isa resisted the urge to roll her eyes. She would never belong to anyone.

“I assume there will be rules to this little arrangement,” she said, trying to keep her voice even.

Adrian smirked. “Smart girl.”

She ignored the way her skin prickled at the way he said those words.

“First rule,” he continued, resting an elbow on the table. “In public, we’re a perfect couple. You smile, you play your part, and you don’t question me.”

Isa arched a brow. “And in private?”

He leaned forward, voice lowering just enough to send a shiver down her spine. “In private, princess, you can hate me all you want.”

A muscle tightened in her jaw. “Oh, I intend to.”

“Good,” Adrian murmured, a slow, knowing smirk playing on his lips.

Her father sighed, rubbing his temples. “Isabella, stop testing him. Adrian isn’t someone you want as an enemy.”

Isa’s stomach churned, but she refused to let it show. “That makes two of us.”

For the first time, something flickered in Adrian’s expression—an almost imperceptible shift, like he was amused but also intrigued. He leaned back in his chair, studying her with that unnerving gaze of his.

“I think I’m going to enjoy this,” he said softly.

Isa’s fingers curled into fists under the table.

So will I, Adrian Costa.

Because no matter what, she wasn’t going to lose herself to this world.

Later That Night

Isa locked the door to her bedroom the second she stepped inside.

The second she was alone, she let out a slow breath, pressing a hand to her forehead. She had spent the entire evening under the watchful eyes of both her father’s men and Adrian himself. Every move, every word, was calculated.

It had taken everything in her to keep her composure.

She wasn’t naïve. This engagement wasn’t about love. It was about power, survival. But something about Adrian Costa unsettled her more than she wanted to admit.

Not just because he was dangerous.

But because, for the first time in her life, she wasn’t sure she could outmaneuver someone.

A knock at the door made her tense.

She closed her eyes briefly before stepping forward. She knew who it was before she even opened the door.

Adrian stood there, his broad frame filling the doorway. Gone was the composed, amused man from dinner. In his place was someone sharper, more serious.

“What do you want?” Isa asked, keeping her voice cool.

He leaned against the frame, arms crossed. “Your father wants you to move into my estate tomorrow.”

Her stomach dropped. “Excuse me?”

His lips quirked. “Did you think we’d play house from a distance?”

Isa exhaled slowly. “I have school. An internship. A life.”

“I’m aware,” Adrian said. “And I have no intention of pulling you out of it. But until this deal is over, you’ll be under my roof.”

Her pulse quickened. The idea of being trapped in his world, under his watch, made her chest tighten.

“I don’t need a babysitter,” she snapped.

Adrian took a step forward, his presence overwhelming. “No, but you do need protection.” His voice dropped lower. “Your father won’t tell you everything, but I will. There have already been threats against you. Someone put a price on your head.”

The air left her lungs.

He wasn’t lying.

For the first time since this nightmare started, fear crept into her bones.

Adrian studied her reaction before speaking again, softer this time. “You don’t have to like this, Isa. But you have to accept it.”

Isa swallowed hard, her nails digging into her palms.

She had spent years trying to escape this world.

Now, it was closing in on her faster than she could run.

And the worst part?

The only person standing between her and the people who wanted her dead…

Was Adrian Costa.

The air in Adrian Costa’s office felt thick, suffocating.

Isa sat across from him, spine straight, hands clenched in her lap. Every fiber of her being screamed at her to leave, to get as far away from this man as possible. But she knew she couldn’t.

Not when she had just agreed to something that could change her life forever.

She was going to pretend to be his fiancée.

The words still felt foreign in her mind, surreal and utterly insane. She had spent years avoiding this world—keeping her head down, studying law, trying to be something other than a mafia daughter. But now?

Now, she was right back in the middle of it.

Adrian leaned back in his chair, watching her with quiet amusement. The sharp angles of his face remained unreadable, his dark eyes assessing her like she was a puzzle he had already solved.

“You’re awfully quiet, princess,” he mused.

Isa’s jaw clenched at the nickname. “I was just wondering when I officially lost my mind.”

Adrian smirked, his fingers tapping lazily against the desk. “I’d say the moment you walked in here.”

Isa exhaled sharply. “And what exactly do you expect from me in all of this? I agreed to the arrangement, but let’s be clear—I’m not some obedient little puppet you can control.”

Something flickered in his expression—amusement, maybe, or something darker. “I wouldn’t have chosen you if you were.”

His words sent an uneasy shiver down her spine.

“I need this to be convincing,” Adrian continued, his voice calm but firm. “Rinaldi’s men are watching closely, waiting for any sign that I’m weak. If they think this engagement is fake, they’ll come after you.”

Isa frowned. “Me?”

“Yes.” He leaned forward slightly, his presence overwhelming. “If they believe you’re important to me, they’ll try to use you as leverage. And if they suspect you’re just a pawn, they’ll kill you to make a point.”

Her breath hitched, but she forced herself to remain composed. “So, what you’re saying is, I’m walking into a warzone.”

Adrian tilted his head. “You already were, sweetheart. The only difference now is that you’re under my protection.”

Isa wasn’t sure if that made her feel better or worse.

She inhaled deeply, pushing back the panic clawing at her chest. “Fine. Then we should set some rules.”

Adrian raised a brow. “Rules?”

“Yes,” she said firmly. “First, no surprises. If I’m going to do this, I need to know exactly what’s expected of me. Second, no actual wedding. This engagement is fake, and it stays that way.”

His lips twitched. “Disappointed?”

She rolled her eyes. “You wish.”

Adrian chuckled, a low, almost dangerous sound. “Anything else?”

“Yes. We keep this strictly business. No crossing lines.”

His gaze darkened slightly, but he nodded. “Understood.”

Isa studied him, trying to determine if he was taking her seriously. Adrian Costa was dangerous, but the true danger wasn’t just his reputation—it was the way he looked at her, like he saw straight through her.

And that was a problem.

Because Isa had spent her whole life making sure no one ever did.

Isa was given a room in Adrian’s estate—if you could call the massive suite a mere room. The walls were painted in deep, elegant tones, the furniture modern yet luxurious. A large window overlooked the city, the view both stunning and suffocating at the same time.

She dropped onto the bed with a sigh, rubbing her temples.

What had she just gotten herself into?

A knock on the door made her sit up.

“Come in,” she called, already bracing herself.

The door opened, and Dante stepped inside, his usual smirk in place. “Comfortable?”

She shot him a dry look. “Like a princess in a gilded cage.”

Dante chuckled. “That’s the spirit.” He leaned against the doorframe, arms crossed. “Adrian asked me to give you this.”

He tossed a phone onto the bed beside her.

Isa picked it up, frowning. “What’s this for?”

“A direct line to Adrian. If anything happens, you call him.”

She scoffed. “I don’t need a babysitter.”

Dante’s smirk faded slightly. “You do now.”

The weight of his words settled in her chest. She wasn’t stupid—she knew the moment she stepped into Adrian’s world, she had put a target on her back.

Sighing, she set the phone down. “I’ll keep it with me.”

Dante nodded, satisfied. Then, after a brief pause, he added, “You know, you might actually survive this.”

Isa arched a brow. “You don’t sound too convinced.”

He grinned. “I’m not. But I like a good underdog story.”

With that, he turned and left, leaving her alone with her thoughts.

Isa stared at the phone, then at her reflection in the window.

She had no idea what the next few weeks would bring.

But one thing was certain—she wasn’t the same girl who had walked into Adrian Costa’s office earlier today.

And she had a feeling she never would be again.