✧ Thirty Days, One Signature
✧ Pairing: Lee Heeseung x Fem!Reader (Y/N)
✧ Genre: Fake Marriage AU, Reality Show AU, Accidental Marriage, Friends to Lovers, Comedy, Fluff, Slow Burn, Idol AU
✧ Synopsis: Due to a reality show mishap and one very unfortunate contract, you and Heeseung are legally married for thirty days. The annulment should be easy. The feelings are not.
The wedding certificate surfaced at 2:13 a.m.
Not in a government office.
But on a giant LED screen in the middle of a live broadcast while six cameramen screamed over each other and a producer fainted somewhere behind the set.
Y/N stared at the document projected above the stage, her mouth hanging open.
Beside her, Lee Heeseung looked equally horrified.
“Wait,” Sunghoon said slowly from the sidelines, holding a cue card upside down. “Are you guys… actually married?”
The studio fell into complete silence.
Then Jake burst into laughter so hard he slid off his chair.
It had started as a stupid reality show segment.
The producers of Idol House: Chaos Edition thought it would be funny to create fake “marriage missions” where celebrities signed novelty contracts and completed ridiculous couple challenges for points. Cooking together. Matching outfits. Pretending to argue over laundry.
At least that was the plan.
Unfortunately for everyone involved, one intern accidentally mixed the fake marriage forms with authentic district office paperwork borrowed for “realism.” Nobody noticed because the filming location happened to be an actual event hall licensed for civil ceremonies.
And because the universe apparently enjoyed suffering, both Y/N and Heeseung had signed everything without reading it.
And a legally certified officiant standing three feet away.
The network’s legal team discovered the mistake three weeks after filming wrapped.
By then the marriage had already been registered.
“We can annul it, right?” Y/N asked for the fifteenth time.
Three lawyers sat across from her in tense silence.
One finally adjusted his glasses.
“In theory?” she repeated weakly.
The lawyer smiled the way people smiled before delivering terrible news.
“The contract has a technical validity period due to the nature of the filing. Until the court reviews the dispute, you are legally recognized as married for thirty days.”
“Thirty days,” he confirmed.
Beside her, Heeseung leaned back against the couch and covered his face with both hands.
Jay, who had insisted on attending “for emotional support and possible entertainment,” whispered, “This is the greatest day of my life.”
Y/N threw a cushion at him.
The news exploded online within hours.
#HEESEUNGMARRIED trended worldwide.
Then, somehow, #DIVORCEPARTY.
Fans thought it was a marketing stunt at first. Then the official statement dropped.
«Due to a procedural issue involving production documentation, artist Lee Heeseung and civilian participant Y/N are currently involved in legal clarification regarding an invalid marital registration.»
That somehow made things worse.
Now reporters camped outside HYBE.
Memes flooded every social media platform.
Someone edited wedding photos of Y/N and Heeseung despite there being no actual wedding photos.
Ni-ki printed one out and framed it.
“You don’t have to move in,” Heeseung said carefully two days later.
Y/N stared at him across the company conference room.
The legal advisor cleared his throat awkwardly.
“Due to public scrutiny and concerns over media interference, it may strengthen your annulment case if you demonstrate cooperative domestic behavior instead of apparent fraud avoidance.”
Jay burst into laughter again.
Jungwon looked exhausted already.
“You’re saying,” Y/N said slowly, “that we have to live together.”
“For thirty days,” the advisor confirmed.
Heeseung dropped his head onto the table.
Moving into Enhypen’s dorm was not part of Y/N’s life plan.
Especially not as someone’s accidental wife.
The members reacted exactly as badly as expected.
Jake greeted her at the door with, “Welcome home, sister-in-law.”
Sunghoon almost choked on water trying not to laugh.
Sunoo immediately dragged her into the kitchen to discuss skincare routines like they’d known each other for years.
Jungwon apologized every ten minutes for the chaos.
Ni-ki asked if he could call her “Mrs. Heeseung” just to annoy him.
“No,” Heeseung said instantly.
“Yes,” Ni-ki answered at the same time.
The first week was unbearable.
Not because Heeseung was rude.
That would have been easier.
Instead, he was painfully considerate.
He moved his gaming equipment out of the spare room so she could have privacy. He labeled shelves in the fridge because she mentioned liking organization. He left snacks outside her door after long days because he noticed she skipped meals when stressed.
And somehow that was worse.
Because Y/N had prepared herself to dislike him.
She hadn’t prepared for kindness.
One night she wandered into the kitchen at 1 a.m. unable to sleep and found him sitting on the counter eating cereal straight from the box.
He looked up in surprise.
“Nightmare,” she muttered.
For a moment neither spoke.
Rain tapped softly against the windows.
The dorm lights were dim except for the stove lamp glowing gold across the kitchen.
“You know,” Heeseung said eventually, “if this bothers you too much… I can stay somewhere else.”
“Yeah, but you didn’t ask for any of this.”
That realization hit unexpectedly hard.
For weeks she’d been so consumed by her own humiliation she forgot he was trapped too.
Heeseung rubbed the back of his neck awkwardly.
“My mom keeps asking if she should send wedding gifts.”
Y/N snorted before she could stop herself.
It was the first genuine moment between them.
And somehow the beginning of everything.
The media only got more aggressive.
Dispatch followed them constantly.
Every accidental interaction became a headline.
HEESEUNG CARRIES WIFE’S SHOPPING BAGS
MARRIED COUPLE SPOTTED ON SECRET DATE
Fans analyzed every frame of every livestream.
One clip of Heeseung unconsciously fixing Y/N’s hood before she walked outside reached three million views in a day.
“Why are people zooming into my fingers?” he asked in horror.
“Because apparently your pinky touching my sleeve is romantic.”
Jake nearly fell off the couch laughing.
Somewhere around day twelve, things changed.
Like realizing the dorm felt calmer when Heeseung was around.
Like noticing he always saved the last strawberry from dessert because she liked them.
Like how he looked for her first in crowded rooms without realizing it.
One evening the members were filming content in the living room while Y/N worked nearby.
Sunoo suddenly asked, “Who confessed first?”
Y/N nearly inhaled her drink.
“We’re not dating,” she coughed.
“But if you were?” Sunoo pressed.
Heeseung glanced up from his phone.
The eye contact lasted barely a second.
Ni-ki gasped dramatically.
“Stop being weird,” Heeseung muttered.
But his ears had turned red.
The storm hit on day nineteen.
A tabloid released articles claiming the marriage was fabricated for publicity.
The backlash was immediate and vicious.
People called Y/N manipulative.
She stopped checking her phone after the first thousand comments.
That night she sat alone on the dorm rooftop wrapped in a hoodie, trying very hard not to cry.
The door creaked open behind her.
Heeseung walked over quietly holding two cans of soda.
“I figured you’d be here.”
She accepted the drink without looking at him.
“No,” he said firmly. “They hate rumors.”
Heeseung was silent for a moment.
“You think it doesn’t still hurt?”
That made her look at him.
For the first time she saw the exhaustion beneath his calm expression. The pressure. The endless scrutiny. The way idols learned to carry pain elegantly because cameras never stopped rolling.
He sat beside her on the concrete ledge.
“When I debuted,” he said quietly, “I thought if I worked hard enough people would only see good things about me.”
“And eventually you realize people see whatever they want.”
The city lights reflected in his eyes.
“But the people who matter,” he continued, “they stay.”
“Why are you being nice to me?”
He looked genuinely confused.
The answer should’ve been simple.
Instead her chest tightened painfully.
On day twenty-four, they accidentally went viral again.
This time because Y/N fell asleep during a movie night and unconsciously leaned against Heeseung’s shoulder.
The members noticed immediately.
Jay silently filmed everyone’s reactions while Jake covered his mouth trying not to scream.
Sunghoon whispered, “No way.”
Heeseung, meanwhile, froze entirely.
Y/N slept peacefully against him completely unaware that the room had entered collective cardiac arrest.
he adjusted the blanket around her shoulders.
The clip spread online within hours.
Fans collectively lost their minds.
“You know what’s terrifying?” Jungwon said later.
“You two act married even when you forget the cameras exist.”
Neither Y/N nor Heeseung had an answer for that.
Somehow they’d fallen into habits naturally.
Waiting for each other before meals.
Texting each other first about stupid things during the day.
It stopped feeling temporary.
And that scared both of them more than the legal paperwork ever had.
Day twenty-nine arrived too quickly.
The annulment hearing was scheduled for the next morning.
One signature and everything would disappear.
Y/N stood in the kitchen unable to sleep again.
A familiar voice appeared behind her.
Heeseung leaned against the doorway quietly.
Neither mentioned what tomorrow meant.
“You know… when this started, I thought thirty days would feel impossible.”
The question lingered heavily between them.
Y/N looked down at her hands.
Close enough that her heartbeat turned traitorous.
For once Lee Heeseung looked nervous.
Not idol-nervous. Not camera-nervous.
“I think,” he said carefully, “somewhere between the legal disaster and Sunghoon almost setting the kitchen on fire…”
A laugh escaped her unexpectedly.
“I fell in love with you.”
Y/N stared at him for a long moment before whispering:
“This is probably the worst confession timing in history.”
Heeseung groaned dramatically.
“Please don’t reject me legally and emotionally at the same time.”
She laughed so hard tears filled her eyes.
And before she could overthink it—
before fear could interfere—
she reached for him first.
His hands found her waist instantly like instinct.
The kiss felt warm and dizzying and long overdue.
When they finally pulled apart, both breathless, Heeseung rested his forehead against hers.
“Should we still annul the marriage?”
“Hm. Maybe we should stop accidentally getting married first.”
He laughed softly against her lips.
Somewhere down the hallway, a door slammed open.
“I KNEW IT—” Jake screamed.
Followed immediately by six other voices losing their minds.
Heeseung closed his eyes.
“We’re never going to know peace again.”
Neither of them minded anymore.
The problem with confessing your feelings in a dorm full of curious idols was that absolutely nobody respected privacy.
The second Jake screamed, every door in the hallway flew open.
Then Sunghoon, who somehow arrived carrying a bag of chips despite having been asleep less than ten seconds earlier.
Y/N and Heeseung jumped apart so fast they nearly tripped over themselves.
Unfortunately, the damage was already done.
Y/N contemplated climbing out the nearest window.
"No way," Ni-ki whispered dramatically.
Jake pointed at them like he'd just discovered a new species.
"We know they kissed," Jay replied.
Sunoo immediately burst into tears.
The next morning was somehow worse.
Because now they had to attend the annulment hearing.
After spending half the night being interrogated by six overexcited witnesses.
The drive to the courthouse was painfully quiet.
Y/N sat beside Heeseung in the back seat.
Their hands occasionally brushed.
Neither knew what to say.
They spoke simultaneously.
The tension eased slightly.
"Are you scared?" he asked.
Y/N looked out the window.
The honesty made her smile.
Because for all the confidence he showed on stage, Heeseung wasn't fearless.
Maybe that's why being around him felt so easy.
The hearing itself lasted less than thirty minutes.
After thirty days of chaos.
Thirty days of headlines.
Thirty days of accidental marriage.
The judge reviewed the documents carefully.
Listened to the network's legal explanation.
Then adjusted his glasses
"You two accidentally entered a legally recognized marriage due to production negligence."
"You did not intend to become married."
The judge looked down at the paperwork.
"And yet according to witness testimony..."
The judge glanced toward the stack of statements.
"...you have been functioning as a married couple for nearly a month."
Y/N wanted the floor to swallow her.
Beside her, Heeseung looked equally horrified.
The witness statements had come from the members.
Which was already a terrible sign.
The judge cleared his throat.
"One witness claims you cook together."
"Another says you wait for each other before eating."
"One statement contains six pages regarding emotional compatibility."
"Someone also submitted a chart."
"That was Jay," Heeseung said instantly.
The judge finally set the documents aside.
"The marriage can absolutely be annulled."
Y/N's stomach dropped unexpectedly.
Because this was what she'd wanted.
So why did it suddenly feel wrong?
Heeseung was already looking at her.
The same realization seemed to hit both of them simultaneously.
Because neither looked relieved.
Then he asked the most dangerous question imaginable.
"Do either of you still wish to proceed?"
The network representatives froze.
Even the court clerk looked interested now.
Y/N's heartbeat pounded loudly in her ears.
Beside her, Heeseung took a breath.
Every head turned toward him.
And before anyone could stop him—
before legal teams could panic—
before common sense could intervene—
Three hours later, every major entertainment outlet in South Korea had posted updates.
The headlines were catastrophic
HEESEUNG REFUSES ANNULMENT
ACCIDENTAL MARRIAGE BECOMES INTENTIONAL
Y/N wasn't even surprised anymore.
At this point a meteor could strike the building and she'd simply ask if Dispatch had photographs.
"What have we done?" she asked.
They sat on a bench outside the courthouse.
Reporters crowded the street beyond security barriers.
The world felt louder than ever.
Close enough that their shoulders touched.
"I think," he said carefully, "I may have ruined our lives."
The first relaxed one she'd had all day.
"I definitely ruined our lives."
"If we're ruining our lives, we might as well do it together."
For a second he simply stared.
The one that reached his eyes.
The one she secretly liked most.
Like they belonged there.
The company nearly had a collective breakdown.
Then emergency meetings about the previous meetings.
Legal departments panicked.
The members found everything hilarious.
"You rejected freedom for love," Jay said.
Heeseung threw a pillow at him.
A week later the story had spread internationally.
Surprisingly, public reaction softened.
People stopped focusing on the mistake.
Stopped focusing on the scandal.
Instead they focused on something else.
The fact that two people who were never supposed to meet this way had somehow found each other anyway.
The absurdity became almost romantic.
Three months later, Y/N stood backstage at one of Enhypen's concerts.
The arena roared with energy.
Lightsticks illuminated the darkness like stars.
Heeseung was preparing for the final stage when he spotted her waiting near the side entrance.
His face immediately brightened.
The reaction happened so naturally he didn't even realize it.
Jake nearly collapsed laughing.
Sunghoon rolled his eyes.
Jungwon sighed like a tired parent.
"He does that every time."
"Every time," Jay agreed.
After the concert ended, Heeseung found her immediately.
The crowd was still chanting outside.
The members were running around nearby.
Staff hurried through the corridors.
Yet somehow the moment felt strangely private.
Heeseung gently brushed a loose strand of hair behind her ear.
One he'd done countless times now.
Still capable of making her heart race.
His smile turned teasing.
"We technically never had a real wedding."
The excitement on his face was immediate.
Because somehow that sounded perfect.
Everything their accidental beginning hadn't been.
His entire face softened.
Every ounce of teasing disappearing.
Like hearing those words still surprised him.
"I love you too," he whispered.
And for once there were no cameras.
Just two people whose story had started with an accident—
And continued because they chose each other.
