The sun was bleeding orange across the desert sky as the Rustbucket rolled to a stop near a forgotten rest stop. Dust settled in lazy swirls as Grandpa Max stepped out, stretching his back and muttering something about setting up camp before dark.

Inside, the air was tense.

Gwen sat hunched at the tiny fold-out table, fingers wrapped around a cold bottle of water she hadn't touched. Her eyes tracked Ben's every move from behind a curtain of auburn hair. He was pacing near the back, pretending to look for his toothbrush, pretending nothing was wrong.

But everything was wrong.

"Stop that," she said quietly.

Ben froze. "Stop what?"

"Pacing. Acting like we didn't—" Her voice caught in her throat. "Like nothing happened last night."

He turned slowly, the dim RV lights catching on the edge of something vulnerable in his eyes. "What do you want me to say, Gwen? That it was a mistake? That we crossed a line we can't uncross?"

"I want you to admit that you wanted it just as much as I did."

Silence stretched between them like a fault line.

Outside, Max laughed at something on the portable grill. Inside, the air felt heavy—like they were breathing secrets instead of oxygen.

Ben moved closer, stopping just a few feet from her. "This isn't just about last night. It hasn't been for a while."

"I know," Gwen whispered. "That's the problem."

/

It had started as a fight.

The kind that always came after too many days on the road, too many alien attacks, too much tension that had nothing to do with monsters and everything to do with what simmered beneath the surface.

Ben had stormed off after their latest argument—something stupid about strategy, about her acting like she was in charge—and Gwen had followed, because she always did.

They found themselves behind an abandoned gas station, moonlight casting silver shadows across the cracked pavement.

"You're impossible," Gwen snapped, arms crossed, voice low.

Ben turned to her, jaw clenched. "You think you're always right. You don't listen. You don't trust me."

"I trust you more than you know," she shot back.

Something in her voice made him pause. The words hung in the air like electricity before a storm.

"Then why do you look at me like I'm the enemy?"

"Because I don't know how else to look at you without giving everything away," she whispered.

His expression shifted—anger dissolving into something else. Something real.

He stepped closer. Close enough to see the freckles across her nose. Close enough to feel her breath.

"We can't," he said, but he didn't step back.

"I know."

Then their mouths collided—desperate, reckless, wrong.

And nothing had been the same since.

Back in the present, Gwen stared at the floor, heart hammering.

"We crossed the line," she said softly. "And I don't think we're coming back."

Ben didn't deny it. Outside, the night settled over the desert like a secret keeping watch.


The RV was quiet. Too quiet.

Max had gone into the nearby town for supplies, leaving Gwen and Ben alone inside the small space that suddenly felt too intimate, too full of unspoken things.

Steam still clung to the bathroom mirror as Gwen braced herself over the tiny metal sink. Her breath came shallow, her eyes hazy. She could still feel the ghost of his touch—his hands, rough and certain, trailing across the curve of her spine the night before.

Her back had arched into him without hesitation, without thought. It was instinct now—how her body responded to his, like it had been waiting.

She stared into the mirror, catching the flush in her cheeks, the way her red hair clung to her neck in wet strands. She had let it down today. For herself. Maybe for him. She didn't want to think too hard about the why.

But when she stepped out of the bathroom and saw him looking at her like that—like she wasn't just Gwen, wasn't just family—her breath caught again.

Ben sat on the edge of the bench, pretending to check his Omnitrix. But his eyes gave him away. They drifted down her legs, lingered at the curve of her hips.

He swallowed hard.

"You wore your hair down," he said, voice rough.

"Yeah." Gwen pretended not to notice the way his gaze locked on her again, more hungry than curious. "Is that a problem?"

"No," he said. "It's… not a problem."

Their eyes met, and the air felt too thick to breathe.

He stood slowly, crossing the small space between them in two strides. His hand reached up—hesitating—then gently slipped through her hair before dropping lower. Gwen didn't stop him. She leaned in, fingers brushing his shirt, grounding herself.

"I can't stop thinking about it," he murmured. "About you."

She didn't reply. She didn't have to.

Ben's fingers traced her jawline like he was memorizing her face.

It wasn't rushed, or heated like the night before. It was slower now. More dangerous, because this wasn't about impulse—it was about choice. About wanting her in the full light of day, consequences be damned.

"You shouldn't look at me like that," Gwen whispered.

"Like what?"

"Like you're about to kiss me again."

He didn't answer. His thumb brushed across her bottom lip.

"You think I don't know this is wrong?" he said finally. "You think I haven't tried to stop?"

She looked up at him, heart pounding, voice low. "Then why don't you?"

He swallowed. "Because when I'm around you… nothing else feels real."

The silence between them was deafening. And then—his hands were on her waist. Not grabbing, not groping. Just holding. Steady. Like she was something fragile he was afraid to break.

Gwen stepped forward, closing the space between them. Her forehead rested against his chest, listening to the wild rhythm of his heart.

"I used to think I'd never be like this with anyone," she murmured. "But then there was you. And now… I don't know who I am without this."

Ben's arms tightened around her. "You're Gwen," he said. "You're still the smartest person I know. Still my cousin."

She laughed softly, bitterly. "Cousin don't do this."

Before he could answer, the distant crunch of tires on gravel snapped them both back to reality.

Max.

They pulled apart like the moment had shattered around them, scrambling for space, silence, normalcy. Ben grabbed the nearest book, pretending to read. Gwen turned her back, steadying her breath.

The door creaked open.

"Kids?" Max's voice was cheery, oblivious. "Hope you're hungry—grabbed burgers from that diner down the road."

"Yeah," Gwen called out, forcing a smile. "Starving."

But her hands were still shaking.

And Ben… he couldn't stop glancing at her.


The hum of the RV's generator was the only sound as night folded in around them.

Gwen sat on the bench with her legs tucked beneath her, pretending to read. Ben leaned against the kitchenette, arms crossed, watching her through the dim lighting. Her red hair fell across her face in waves, and every few seconds, she would glance up—eyes sharp, thoughtful, and burning.

"Don't stare," she said without looking up from the page.

"I'm not," Ben replied too quickly.

She finally looked at him.

"You've been watching me since grandpa went to sleep."

Ben hesitated. "You've been watching me, too."

The book closed slowly.

Silence thickened around them like fog. Gwen stood, walking over to him with deliberate steps. The distance between them disappeared in seconds, and when she stopped, she was close enough that he could see the flecks of gold in her green eyes.

"I remember what you said," she whispered. "About being careful. About not getting hurt."

"I meant it," Ben said, voice soft.

"Good," she replied. "Because if you get yourself killed again, I'm not going to be the calm, collected one."

"I don't think you ever were," he teased, trying to ease the tension.

But she didn't smile.

Instead, she reached up, fingers brushing a fading bruise on his neck. "You scared me."

His breath caught. "I know."

Her hand lingered on his skin.

He didn't pull away. He couldn't. Gwen was right there—fire and control, steel and softness. Every part of him wanted to lean in, close the space, let the weight of everything crash down.

But Gwen moved first.

She pressed her forehead to his, eyes closed.

"I hate how right this feels," she murmured.

He didn't answer with words. Just slid his arms around her waist and held her, like it was the only thing anchoring him to the world.

Outside, the desert wind blew softly against the windows. Inside, the air between them crackled—not with spells or alien tech, but something far more dangerous.

Emotion. Desire. Need.

And the terrifying realization that no matter how wrong it was, they were already in too deep.

Their moment broke—not from guilt or hesitation, but from the sudden blare of the old TV echoing from Max's room.

A sharp voice cut through the air:

"This just in—chaos downtown! Reports confirm an alien force is attacking city property. Citizens are calling for one name: Ben Tennyson. Where is our hero?"

Ben and Gwen froze, eyes snapping toward the sound.

She pulled back slightly, the heat of their closeness still lingering, then leaned in just enough to whisper in his ear. Her breath sent a shiver across his skin.

"Go get them, hero," she murmured. "But be careful while you're out there kicking alien butt."

Ben grinned. "Right, Gwen… I'll be safe."

He held up his wrist, the Omnitrix glowing to life with pulsing green light. "It's hero time!"

The dial turned with a click, and a bright surge of emerald electricity burst across the RV. In a flash of blinding light, Ben transformed—tall, towering, and armored—into Ultimate Humungousaur.

The RV rocked slightly with the sheer size of him. He flexed with a playful growl, giving her a wink.

"Ultimate Humungousaur, Gwen!"

Gwen crossed her arms, eyes trailing up the massive figure with a slow smile.

"Mmm, looking good, Ben. Now go save the town, hero." She bit her lip slightly—just enough for him to notice.

"I will!" the deep, booming voice of Humungousaur rumbled as he ducked under the RV doorway and thundered outside.

The door clanged shut behind him.

Gwen stood alone for a beat, the fading sparks of green light still dancing in the air around her. Her smile softened into something more wistful as she looked at the spot where he'd stood.

"Come back to me in one piece, dork," she whispered.


The moment Ben thundered out into the night, the RV felt twice as quiet. Gwen stood by the window, arms crossed, heart racing for reasons she didn't want to admit too loudly—not even to herself. She turned the tiny mounted TV toward her and flicked the volume up. The live news report had cut to a shaky helicopter cam feed of downtown. And there he was.

Ultimate Humungousaur.

All ten feet of green-scaled power and swagger, tossing alien attackers like they were made of paper. Cars were overturned. Buildings scorched. Civilians ran. But Ben… Ben was in control. Confident. Dangerous. Kind of hot.

Gwen leaned forward slightly, eyes narrowing with focus—but her lips curled, just a little.

There was something about the way he moved in that form. Strength without ego. Power used to protect. She knew that alien form well… and the guy inside even better.

"Come on, dino boy," she whispered. "Show off just a little more."

As if on cue, the camera caught a close-up of Humungousaur throwing a smug flex after tossing a baddie into a lamppost. Gwen rolled her green eyes but laughed, biting her lip.

"Still such a dork…"

"Who's a dork?"

Gwen spun, startled.

Max stood in the hallway, drying his hands with a rag, brow arched like a man who'd definitely just seen something.

Gwen instantly straightened up. "Nothing. I—I was watching the news. Ben's on-screen."

Max walked closer and glanced at the screen. "Yep. Looks like he's got things under control." He eyed her again. "You were really… focused, there."

Gwen forced a shrug. "I'm just worried about him. That's all."

"Mmm." Max scratched his chin. "Because from the way you were biting your lip, I thought you were more than just worried."

Gwen blinked. "Excuse me?"

"Kiddo, I've been alive a long time. I know a look when I see one. You were glowing."

"I was—what? No. Gross. Ben's my cousin."

Max narrowed his eyes, still unconvinced. "Mhm."

Gwen folded her arms, turning her attention back to the screen, heart now pounding for a very different reason. "Shouldn't you be asleep or doing… Grandpa stuff?"

"Just saying," Max grumbled as he walked back toward his bunk. "If you're crushing on your cousin, at least wait until the city's not on fire."

Gwen nearly choked on air. "What?! I'm not—ugh!"

But Max was already gone who didn't mean it as he teased her.

She slumped back on the bench, face burning.

Then, quietly, eyes returning to the screen as Ben sent the last alien flying—

"…Still kind of hot, though."

/

The RV door creaked open with a burst of desert wind and the scent of scorched pavement.

Ben ducked inside, back in human form, panting slightly as the Omnitrix on his wrist powered down with a soft whirr. His shirt was torn at the sleeve, dirt smudged across his jawline, hair tousled from the fight—and somehow, that made him look even better.

Gwen snapped her gaze away fast enough to pretend she hadn't just been staring at the TV for the last half hour.

"You're back," she said, glancing up from her spellbook like she hadn't been counting every minute.

Ben dropped onto the bench across from her, letting out a long breath. "Yup. Aliens handled. Power lines saved. Street vendors grateful."

She tried not to smile. "Did one of them give you free churros again?"

"…Maybe."

He grinned, tired but proud. Gwen reached over, brushing a streak of ash from his cheek. Her fingers lingered—just a second too long.

"You're getting better," she said softly. "More control. Less wreckage."

"Thanks," he murmured. "Means a lot, coming from you."

Their green eyes locked.

It should've felt normal. Familiar. But it didn't. Not anymore.

Not after the last few days. Not after whispered confessions, healing spells laced with emotion, and the way she watched him when she thought no one noticed.

Ben leaned in, elbows on his knees. "So… how bad was it?"

"What?"

"My performance," he said, nudging her lightly. "On TV. Did I look cool? Heroic? Maybe just a little awesome?"

Gwen smirked. "You were fine."

"Just fine?"

"Well, the flex was a little much."

Ben laughed, rubbing the back of his neck. "Hey, I saw the camera. I knew you'd be watching."

She looked at him for a long moment, smile fading into something quieter, deeper.

"I always watch," she said.

Silence settled. The kind that only two people with too many unspoken feelings can create.

Then—

"GRANDPA!" Ben called, standing abruptly, voice too loud. "I'm back! Everything's cool!"

No answer.

"GRANDPA?" Gwen echoed.

Ben peeked into the back. "Out cold. Snoring like a lawnmower."

They both paused.

Alone.

The RV buzzed softly with the hum of tech and desert wind.

Ben looked back at her. "So… what now?"

Gwen stood, walking toward him slowly, deliberately.

Her hands brushed his, fingers curling. "Now?" she said, voice low. "Now you let me thank my hero properly."

Max's snores hummed from the back room—steady, oblivious, almost like background noise in a moment neither Gwen nor Ben would ever forget.

Gwen stood in front of him, close enough that Ben could feel the heat of her skin, see the way her chest rose and fell just a little faster than normal.

Her fingers still brushed his.

Neither of them moved.

Not yet.

"You scared me tonight," she whispered, looking up at him. "When I saw you on that screen, all banged up, throwing yourself into danger…"

Ben swallowed hard, nodding. "I know. I'm sorry."

She didn't answer right away. Her eyes searched his, dark and uncertain, flickering between restraint and something she could no longer bury.

"No more waiting," she murmured. "No more pretending."

And then she leaned in.

Soft. Slow. Like she wasn't sure if she'd break by touching him—or if he would.

Her lips met his.

It wasn't rough or hungry. Not yet. It was just… real. A quiet surrender. Months of glances, brushes of skin, whispered words and hidden feelings poured into a single, breath-stealing kiss.

Ben froze for half a second—then melted into it.

His hands found her waist, pulling her closer. Gwen's fingers curled into his shirt, holding tight like she was afraid he'd disappear again.

The kiss deepened. Her lips parted slightly, inviting more, and Ben gave it—carefully, desperately. Like kissing her was the only way he could breathe.

When they finally pulled back, foreheads pressed together, their breaths mingled.

Neither spoke at first.

Then—

"Gwen," Ben whispered, voice low and ragged. "Are we really doing this?"

Her eyes opened, and she gave him a small, determined smile.

"We already are."

And somewhere, in the back of the RV, Max snored on… completely unaware that his two grandkids had just crossed a line they could never uncross.


The Morning After

Steam curled in the air as a naked Gwen stepped out of the shower, skin still warm, hair damp and wrapped in a towel. She stood in front of her bathroom mirror, condensation clouding the glass.

With one hand, she wiped it clean—revealing her own reflection.

There it was. That smile.

Soft. Satisfied. Smug, even. The kind of smile that lingered after a night of pleasure… and now secrets.

A deep blush crept across her cheeks as flashes from the night before danced through her mind—Ben hands, his mouth, the way he made her feel like she was the only girl in the world. Her body still buzzed from it, from him. But the thought of Ben's hands on her, his lips on hers, was too tempting to resist. His hands roaming over her body. Gwen gasped as he cupped her ass, her breath hitching as he lifted her onto the counter. She wrapped her legs around him, pulling him closer, her hands tangling in his hair.

Ben's lips were on hers, his tongue darting into her mouth, tasting her. Gwen moaned, her hands sliding down his chest, her fingers tracing the lines of his muscles. She could feel his hardness pressing against her, and she couldn't help but grind against him, her body aching.

Ben's hands slipped under her top, his fingers finding her wetness. Gwen gasped, her back arching as he began to tease her. She could feel her orgasm building, her body tensing as she neared the edge.

"Ben," she gasped, her voice strained. "I'm gonna come."

Ben's response was to thrust two fingers inside her, his thumb finding her clit. Gwen cried out, her orgasm crashing over her, her body shaking with pleasure.

Ben didn't give her time to recover, his fingers still working inside her, his thumb still teasing her clit. Gwen moaned, her body still sensitive from her orgasm, but she didn't want him to stop. She wanted more.

She pushed Ben back, her hands on his chest. He looked at her, his eyes dark with desire, and she knew he was as lost in this as she was.

"I want you to do me," she said, her voice low and husky. "I want you to do me right here."

Ben didn't need to be told twice. He stepped closer, his hardness pressing against her. Gwen moaned, her hands reaching down to guide him inside her.

Ben thrust into her, his hands gripping her hips. Gwen cried out, her body arching against his. She could feel him filling her, his hardness sliding against her sensitive walls.

"Gwen," Ben gasped, his voice strained. "You feel so good."

Gwen could only moan in response, her body lost in the pleasure of Ben's thrusts. She could feel her orgasm building again, her body tensing as she neared the edge.

Ben's hand slipped between them, his thumb finding her clit. Gwen cried out, her orgasm crashing over her, her body shaking with pleasure.

Ben followed her over the edge, his body tensing as he came. Gwen could feel him pulsing inside her.

They stayed like that for a moment, their bodies entwined, their breaths mingling. Then, slowly, Ben pulled away, his eyes meeting Gwen's.

Because behind the sparkle in her green eyes and that subtle glow, there was something darker. "I've done it," she whispered, brushing her fingers across her lips. "I've really done it."

She bit her bottom lip, her voice thick with conflicted heat.

"Yep. It's official—I'd sleep with my cousin."

Her eyes drifted—past herself in the mirror, to the slight movement behind her.

Ben.

He was still shirtless, towel slung over his shoulder, his lean frame walking past the hallway behind her. The way his body moved made her heart skip, made her breath hitch. She couldn't stop looking.

Her eyes fell to the reflection of his chest… then lower… and her blush deepened.

How could something so wrong feel so right?

She can't tell grandpa what she did even if her grandpa joked about her having a crush on Ben.

To be continued

Hey readers!

Thanks so much for checking out Lines We Cross. This fic is a slow-burn, emotional drama with heavy romantic tension, character depth, and just the right amount of danger. It's about two people caught in a whirlwind of duty, family, and forbidden connection—and choosing to chase what feels right, even when the world says it's wrong.

I wanted to explore Gwen and Ben in a different light—older, more emotionally layered, and dealing with the consequences of growing up too fast while saving the world. Expect late-night moments, intense confessions, close calls, and the line between heroism and personal desire getting blurrier each chapter.

Appreciate your support, and I'm always open to thoughts, comments, or suggestions for future chapters. Stay tuned—this is just the beginning.