"Desire is a chain. Once it wraps around your heart, there's no escaping it."
The soft hum of cicadas echoed beyond the cracked window as the summer heat lingered into the night. Kaito lay in bed, sweating. His T-shirt clung to his chest. The fan oscillated lazily, failing to stir the suffocating air.
He had that dream again.
The same one. The one he couldn't talk about.
It wasn't violent. It wasn't horrifying. But it made his heart pound and his body ache in ways he didn't understand. In that dream, she always stood there—Aoi—barefoot, wrapped in a towel, lips parted slightly like she was about to say something but never did.
And then she'd lean in. Too close. Her breath on his cheek. Her voice in his ear.
"Touch me, Kaito."
He jolted upright, heart hammering. "Shit…"
A light knock on his door.
Kaito froze.
The door creaked open. Her voice, cool and casual, slipped through the gap. "You're not asleep?"
Aoi.
She stepped in without waiting for a response. Wearing... next to nothing. A sheer black lace robe draped over her shoulders, and beneath it—was that lingerie? It clung to her curves like water, thin and floral, dangerous and beautiful.
He swallowed hard, eyes darting to the floor. "W-What are you doing?"
She smirked, brushing a lock of her black hair behind her ear. "Bathroom light's broken. I need to use yours."
"There's a guest one downstairs—"
"I don't like it," she said flatly, walking past him.
The scent of rose and heat followed her like a shadow.
He watched her disappear into the bathroom connected to his room, heart slamming in his chest.
[SYSTEM INITIALIZED]
Sinbound: Level 0 — VIRGIN
Welcome, Kaito. You have 7 days to commit your first sin. Target: Aoi Takamine.
Reward: Enhanced Appearance +1 | Physical Strength +1 | System Progression Unlocked
Penalty for Failure: Public Exposure of your darkest thoughts.
His eyes widened. "What the hell…"
Was this a joke?
A dream?
The mirror in his room flickered.
[You are now bound to the System of Lust. Each sin awakens your true potential. Each girl is a lock. You are the key.]
His legs trembled. This was crazy. Insane.
And yet... that part of him, the part that always stirred when Aoi was near—was awakening.
The bathroom door opened.
Aoi emerged in a cloud of steam, wiping her neck with a towel. Drops clung to her collarbone, gliding down the valley between her breasts. Her gaze drifted to him.
"What's with that look?" she said, voice low. "You've seen me in less."
"N-No I haven't—"
"Liar," she whispered, stepping closer. Her fingers brushed his chest. "I've seen how you look at me."
His breath caught.
She leaned in, lips almost brushing his. "You think I don't know what you dream about?"
[SYSTEM TRIGGERED: Sin Opportunity Detected.]
Accept? [Y/N]
He hesitated.
Everything in him screamed no.
But his hand moved on its own.
[Y]
The towel fell.
So did everything else.
Aoi straddled him, her eyes half-lidded, breath warm against his neck.
"Don't hold back, little brother," she whispered. "Show me what all those dreams were about."
Their mouths crashed together, tongues tangling, teeth scraping. Her body pressed down on him, firm and hot and trembling. He gasped as she guided him inside her.
It was tight. Too tight. She groaned as her nails dug into his back.
Kaito's mind exploded. Every nerve felt like fire. His hands found her hips, and instinct took over. He thrust upwards, clumsy at first—then desperate. Her moans grew louder.
"You're better than I thought," she whispered, biting his ear. "Keep going."
His grip tightened. The bed creaked under them. She rocked against him, faster and faster. His body moved on its own.
He was drowning in heat. In her.
She arched her back as her climax hit—hard. Her scream was muffled as she bit his shoulder.
And then—he came.
His vision went white.
Everything stopped.
[Sin Achieved. Transformation Beginning.]
+1 Appearance. +1 Strength. Hidden Trait Unlocked: "Desire Magnet"
Next Target Unlocked: Choose or Randomize.
New Sin Pathways Available.
Kaito stared at his hands. They looked… different. His skin clearer. His jaw felt sharper. His reflection in the mirror shimmered with something new.
Power. Hunger. Temptation.
Aoi shifted beside him, her voice softer now. "Don't tell anyone… what we did."
He turned to her.
"I won't," he said. "No one needs to know."
But the System knew.
And it was just getting started.