A/N: Modern AU, for Chanty420, Marius might be a bit OOC

"What do you mean you're leaving?" Marius's voice rose to match the pitch of a teenage girl's.

"It's just for a week," Cosette said, rubbing his arm. "Father wants me to visit London. He says it'll be a good experience for me to see different cultures."

"When are you going?" Marius asked.

"Tomorrow," Cosette pursued her lips. "I didn't want you to worry and freak. Marius, I'll be back next Sunday."

"Well, we still have tomorrow," Marius said weakly.

"No, we're leaving early in the morning. Just today," Cosette hugged him.

Marius looked like he was going to cry. His brown puppy eyes welled up with tears. "Shhhhhhh, relax. I'm coming back," Cosette said, and Marius nodded.

Cosette and Marius didn't talk about Cosette leaving for the rest of the day. When Marius had to go home, Cosette took a detour to the Musain café.

"Cosette?" Joly frowned as the small blonde entered the back room.

"Don't take this the wrong way, but what are you doing here?" Grantaire asked.

"I need to ask a favor," Cosette said, sitting down next to Jehan.

"What's the favor?" Feuilly asked.

"So, I'm leaving for the week and—" Cosette began.

Everyone groaned "Marius."

"Yes. Please make sure he won't do anything rash? I've been told how he gets when I'm not around," Cosette said desperately.

"Don't worry, we'll keep an eye out for him," Jehan said with a smile.

"Yeah, we will never let him out of our sight. Never," Courfeyrac grinned.

Cosette smiled and stood up, "thank you."

"You're very welcome, Mademoiselle," Jehan said.

Cosette left.

"So, we're now babysitting Marius?" Bahorel said.

"He's a grown man, he doesn't need babysitting," Combeferre said sternly.

"He's Marius. A little boy in a semi-grown body," Courfeyrac grinned.

Monday came, and it was okay. Until someone started pounding on Courfeyrac's door.

"It's 5am!" Courfeyrac screamed, opening the door.

"Cosette just left for the Chunnel!" Marius said. "What if the train crashes and drowns? What if her father decides to never come back?"

"Calm down!" Courfeyrac said. Marius was a mess. His hair was all messed up, his shirt was buttoned up wrong, and he had a smudge of food on his cheek.

Courfeyrac whipped out his phone and sent a text.

Marius duty begins now –Courf

He dragged Marius inside and forced him on the couch. Courfeyrac sat next to him and turned on the TV. "Concentrate," he said. His phone started buzzing with incoming text messages.

Are you serious?!-Bahorel

I call 6pm-R

I'm working this morning, I can drag him along though –Ép

He can help me with my speech-E

Just throw him in a bouncy house –Jehan

Can we still export him? I know a person in Greece-Feuilly

Make him read a book. Or two. –Combeferre

I have some sleeping gas to calm him down –Joly

Why? –Bossuet

Courfeyrac sighed and observed Marius, who was staring into space.

Bahorel, why would I wake up at 5am to make a joke? –Courf

Éponine, you need two eyes on him at all times. Multitasking is not recommended –Courf

Go to sleep Enjolras! –Courf

Tempting, Jehan –Courf

As a last resort, Feuilly –Courf

Combeferre, more like twenty –Courf

Joly, can I borrow some? –Courf

Bossuet, because we told Cosette we'll do this –Courf

Courfeyrac went over and heated up some leftovers for breakfast. Nothing like dinner for breakfast! He came to find Marius's face in a pillow.

"Marius," Courfeyrac said, gently.

"COSETTE!" Marius cried.

"Stop. Suffocating. Yourself." Courfeyrac got the pillow away and threw it across the room. He put the plate of food on Marius's lap.

"I'm not hungry," Marius pouted.

"I got out of my comfy bed at 5am to take you in and heated up breakfast for you. The least you can do is eat it!" Courfeyrac said.

Marius ate slowly. Courfeyrac was forced to stay awake and watch Marius do nothing. He wasn't allowed to sleep, since Marius could spontaneously do something.

Someone knocked around 7:30am. Courfeyrac ran to the door and opened it. "Jehan! I love you so much!"

Jehan blushed but didn't say anything. "How's the puppy?"

"Take him! Please!" Courfeyrac ran into his room and dived onto his bed. Jehan walked over to Marius.

"Come on, we have to go," Jehan said.

"No! You're going to try to take me away from Cosette!" Marius said.

"No, we're just going to the park," Jehan said.

"That's where Cosette and I first saw each other!" Marius burst out crying.

Jehan sighed and took Marius by the hand. He walked past Courf's bedroom, where he could hear snoring. Jehan and Marius walked outside and down the street.

"Aliens…" Marius muttered.

Jehan turned to him. "What was that?" he frowned.

"Alien!" Marius turned and ran away from him. "Cosette, I'm coming for you!"

Jehan ran after him, sending a text as well.

Marius on the run –Jehan

Jehan kept running, looking for Marius. He ran all morning, but couldn't find that boy. Marius was definitely not taking Cosette's trip well. And today was Monday. Jehan hopefully checked his phone.

I'm sleeping –Courf

He's not at a bar –Bahorel

I'll look for him –E

We need to lock him up –Joly

Maybe he went to the airport? –Bossuet

Did you lose Marius already? Joly and Bossuet keep checking their phones! –Musichetta

Jehan sighed, not wanting to deal with an angry Musichetta. Finally, Marius was found.

I've got him. He's in the staffroom right now. –Ép

Don't forget him :) –Jehan

I won't lol –Ép

Éponine put away her phone before the manager saw her. She finished up her shift and got Marius.

"I'm buying a leash," she said.

"I want Cosette!" Marius said.

Times like these, Éponine was glad she chose Enjolras over Marius. She led Marius to her afternoon job and locked him in that staffroom.

Éponine dragged Marius to Enjolras's flat, where she was staying.

"'Ponine, you're back—" Enjolras trailed off as he stared at Marius. He sighed. "I'll make dinner."

Éponine went and got out a board game. "Let's play a game to distract you," she said. Marius nodded and sat down. Éponine was winning when Enjolras came back with dinner. Enjolras sat next to Éponine and put his arm around her waist.

"Cosette loved games," Marius said.

"Cosette isn't dead, she's in London," Éponine said.

"Same difference," Marius muttered, staring at his fork.

"Make sure Marius doesn't kill the couch, I have to pee," Éponine said, getting up.

Marius fell asleep on the floor, his mouth open like a goldfish. "Day one has been completed," Éponine said, leaning against Enjolras.

"Only six more left," Enjolras chuckled.

"Let's head to bed, I'm tired. Combeferre's coming in the morning," Éponine said, yawning.

Combeferre was up bright and early Tuesday morning. He went over to Enjolras's apartment and knocked on the door.

Éponine opened it. "Hey," she said, sleepily.

"Long night?" Combeferre asked, pitifully.

"Marius wouldn't shut up. And then Enjolras would rant for hours. Between those two I got ten minutes of sleep, give or take a couple."

"What does he do?" Combeferre asked.

"Scream and cry about Cosette. If I have to hear another time about her golden hair and blue eyes I'm going to murder someone."

"Well, I have come to take him off of your hands," Combeferre said.

"You'll need this," Éponine handed him a leash. "I bought one last night, after the tenth time. Marius was like 'Cosette, I want to kiss you badly!' and then Enjolras would scream 'No one cares about your lonely soul!' The guy at the pet store understood why I was there at 2am."

"Well Marius is the equivalent of a puppy," Combeferre said, reluctantly taking the leash. Marius appeared at the doorway.

"COSETTE! YOU'VE COME BACK!" He threw himself at Combeferre. Marius frowned and stepped back "You're not Cosette."

"No, I'm Combeferre. Your…friend…sort of…more like acquaintance…point is, I'm spending the day with you," Combeferre said awkwardly.

"But I want Cosette!" Marius whined.

"Don't make me get a matching collar for this leash," Combeferre threatened.

"What if she likes London and wants to stay there? What if she meets someone else?" Marius started crying.

"Let's go," Combeferre pulled Marius out of the apartment and to his class.

Marius followed Combeferre nearly all of the way, before he saw a blonde girl across the street. "Cosette!" Marius screamed and ran across the street, nearly getting hit by a car.

The girl turned and frowned. "I'm not Cosette…"

Combeferre caught up with them. "I am so sorry," he apologized. He grabbed Marius's ear and dragged him the rest of the way.

"I miss her," Marius cried.

"Tuesdays we have Les Amis de l'ABC meetings, come on," Combeferre said.

The back room wasn't crowded, since it was ten minutes early.

Combeferre put the collar and leash on the table, and sat Marius down. Enjolras looked over and smiled.

"I think we can get Jehan to take care of him tonight," he said.

"I feel as if Grantaire and Bahorel should take him. Karma," Combeferre said.

"Yeah," said Enjolras, distributing papers to the people that were coming in.

"So, who's on Marius duty tonight?" Feuilly asked.

"Grantaire and Bahorel," Combeferre said.

"What?!" Bahorel and Grantaire cried out.

"We're going to the bar!" Bahorel said.

"Yeah, why in the world will you trust us?" Grantaire asked.

"I'm counting on you," Enjolras stared straight at Grantaire.

Grantaire sighed and nodded, "Alright, we'll do it Apollo."

"He's your responsibility," Bahorel said.

After the meeting, Grantaire and Bahorel dragged Marius to a local bar. Grantaire put the dog collar on Marius and clipped the leash on.

Grantaire sat next to Marius and ordered two shots. Bahorel was over flirting with some girls.

"A toast!" Grantaire called, lifting up his glass. Marius just whimpered.

"You need to forget about Cosette, she's fine. You'll drive yourself mad with worry," Grantaire said.

"You guys are supposed to be my friends! You're all traitors!" Marius exclaimed, getting up.

Grantaire took the leash and dragged Marius out of the bar and to Marius's apartment. Grantaire's apartment was about to fall down, so he felt like Marius should be in a safe environment. Digging through Marius's pockets, Grantaire found his key.

Grantaire pushed Marius into the bed and went to sleep on the couch. He woke up early Wednesday and went to check the fridge. Nothing.

Grantaire took Marius's wallet and headed to the local grocery store. He bought some milk and eggs for breakfast, and then headed back to Marius's apartment.

Grantaire tried to open the door, but it was locked. Not locked, blocked. Grantaire sighed and tried to push it, but it didn't budge.

"Marius?! Are you in there?!" Grantaire pounded on the door.

"Go away!" Marius cried.

"Did you build a barricade?" Grantaire asked. There was no answer. Grantaire sighed, and pulled out his phone.

We have a situation; Marius built a barricade –R

The response was almost immediately.

Seriously?! –Ép

How strong? –Combeferre

Do we need a cannon ;) –Courf

Where? –E

Not doing this again –Bahorel

Musichetta forbids me and Bossuet from getting involved –Joly

You're on your own –Jehan

Backup is on the way –Feuilly

Grantaire sat down against the door and waited for his friends. Finally, they arrived.

"Took you long enough," he muttered.

"At least it's his place. If anything bad happens to it, it's on him," Bahorel said.

"Why doesn't he just text Cosette?" Enjolras said.

"Because Cosette can't use her phone abroad. Partially because of her phone's plan and partially because of her dad. Besides, Cosette's father constantly checks her phone. I remember one time I called and he answered. We had a lovely discussion, though," Éponine said.

"Lovely discussions with overprotective fathers aside, we need to get Marius out of there," Combeferre said.

"Do we? I mean, can't we just leave him?" Courfeyrac asked.

"We promised Cosette," Jehan said.

"This better be worth it," Éponine said, rolling back her sleeves.

"On three," Bahorel said. "One…two…three…" They ran into the door, and managed to get it open. A huge barricade of furniture was blocking the door. Éponine and Jehan squeezed through and began destroying the barricade. Soon, the barricade was destroyed.

"Marius, where are you?!" Enjolras yelled. Marius appeared at the foot of the steps, a wild look in his eyes, and no clothes on.

"Enemies!" Marius screamed. He ran towards them and out the door.

"Marius come back! You need to get dressed!" Éponine called out after him. She sighed. "I'm not chasing him."

Everyone just stood there, debating whether or not they should associate with the crazy person running around on the streets. Eventually they started looking, but couldn't find him. They accepted defeat, and went back to their respective homes.

Éponine woke up to a million texts on her phone.

I found Marius asleep in some trash cans, naked –Musichetta

I washed Marius for you, he's now squeaky-clean! –Joly

Musichetta's babysitting Marius now –Courf

Marius is responding well to human interactions. He stopped talking, and is now making small sounds –Bossuet

We should be fine, Musichetta's really responsible –R

Éponine smiled and put her phone away.

"News?" Enjolras asked sleepily from next to her.

"Yeah, Musichetta has Marius now," Éponine said, snuggling into Enjolras's warm body.

"Wonderful," Enjolras said, closing his eyes.

Musichetta stared at the three boys in the living room. All three were covered in chocolate.

"What happened? You were making a cake! How could this have gone wrong?" she asked. She turned to Joly. "You were supposed to supervise them!"

"I had to wash my hands again!" Joly protested.

Musichetta pursed her lips and turned to Bossuet and Marius. "Of course we only have one shower. So, it's going to take a while to clean all of you."

"Me and Bossuet can double up," Joly said.

"Fine, just be quick," Musichetta said as the two boys headed into the bathroom.

Musichetta went to inspect the damage in the kitchen. She sighed at the mess. She was hoping for a relaxing free day. She smirked; maybe they could eat all of the chocolate. Musichetta turned back to see Marius run out of the door.

"No!" Musichetta ran outside, but Marius was gone.

Marius is out on the streets covered in chocolate –Musichetta

Follow the dogs –Courf

I may eat him, mwahahaha –R

How? –E

Hahahahahahahahahahahahahahahahahahahahaha –Ép

I'm not doing this –Bahorel

Just leave him –Feuilly

We'll find him, don't worry –Combeferre

I think I can smell him… -Jehan

Bahorel found Marius, sitting on the edge of the fountain. He sighed and walked over to Marius. The fastest way to get him clean was to push him in the fountain, which Bahorel did.

He dragged the now wet and still chocolaty Marius to the Musain café, for the meeting. The meetings were also on Thursday.

"Okay, what are we going to do?" Bahorel asked, dumping Marius on the ground.

"He's a handful," Enjolras remarked.

"Jehan, do you want to take him?" Courfeyrac asked.

"But what if I lose him again?" Jehan freaked.

"It'll be alright," Combeferre said.

"Can we just stay here? Marius seems to like that floor," Feuilly said, nodding to where Marius was sleeping.

"I agree with the Fuel-miser," Bahorel said.

"What?" Feuilly asked, frowning.

"Feuilly, feuil, feul, fuel," Combeferre said from his book. "Same logic as calling me Ferret."

Grantaire started chuckling. "And that logic is flawless."

"Well, there's one little flaw in that flawless logic," Enjolras mocked. "Only you and Bahorel find it funny."

"One person agrees with me, that's enough!" Bahorel high-fived Grantaire.

"Alright, I'm going to get some blankets and pillows," Éponine said.

Éponine came back with a bunch of pillows and blankets. Soon, the Les Amis were all scattered around the room, with Marius in the middle.

That night was uneventful. Marius slept through. He woke up to Enjolras and Combeferre staring at him.

"It's Friday. You have two days left," Enjolras said.

Marius hissed at him, and curled into a circle.

"That was so uncomfortable," Jehan said.

"Eh, I've slept here before often," Grantaire said, rubbing his neck.

"Whose idea was this?!" Feuilly cried.

"Yours," Bahorel said, stretching.

"Never listen to me again," Feuilly muttered.

"Marius didn't escape," Éponine pointed out.

"He's still like a wild animal," Joly said.

"So, what shall we do today?" Bossuet asked.

"Me and Enj are going on a date, so have fun," Éponine smirked, getting up and dragging Enjolras with her.

"I don't want to deal with him again," Grantaire said.

"Here, I'll take him. I have work, but he can help," Feuilly said.

"Just lock him in a room. That worked for me," Éponine said, leaving.

"I'll think of something. Do you still have the leash?" Feuilly asked. He was giving the leash and left with Marius growling behind him.

Jehan was at a café with Courfeyrac around lunchtime, when Feuilly walked over to him. His work-clothes were torn.

"I can't deal with him! He bit me! And chewed my clothes! And then the fans! My lunch break is almost over, please take him!" Courfeyrac grabbed the leash while Jehan hugged Feuilly.

"Now we have the dog," Courfeyrac said, looking at Marius. "Should we check him for rabies?"

"I think he's good. He's not foaming at the mouth," Jehan said. "Actually, he is."

"If he starts marking his territory, we're locking him up," Courfeyrac said.

"I wanted to go to the museum!" Jehan said.

"Yeah, looks like our plans are canceled this afternoon," Courfeyrac said glumly.

"Oh well, it'll be fun! Let's go to the park," Jehan said. They walked around the park with Marius, crawling on all fours. Marius kept chasing squirrels and cars.

Friday night, they all went to Combeferre's apartment, which was the largest. They brought food, drink, blankets, and pillows. Everything they need for their lock-down.

The lock-down was going pretty okay. Marius would just curl in a corner and growl if anyone came to close. He was shaking. Joly wanted to check him, but Marius might bite his hand off.

"Hey guys, the princess will be back to her frog on Sunday," Éponine reminded them. They never said Cosette's name in front of Marius anymore, since that would set him off.

Courfeyrac awoke to Marius at the window, howling at the full moon. "She needs to get here soon," he muttered before putting a pillow over his head.

Bahorel didn't want to spend his Saturday locked up in Combeferre's apartment with everyone. Once in a while, someone would leave to get some supplies. Marius would occasionally chew on stuff. Éponine bought him a chew toy, which he took gratefully. Grantaire was walking into the kitchen when Marius attacked him.

"Get him off!" Grantaire screamed as Marius bit into his leg.

It took everyone's fullest strength to pry Marius off of Grantaire. They shoved Marius into the bathroom, and Joly gave Grantaire a stress-ball.

"That dude's possessed!" Grantaire cried out.

"…I think R's right…" Éponine said.

"Combeferre, do you know how to do an exorcism?" Bossuet asked.

"I don't know…I don't think we have to skills…or the materials…" Combeferre trailed off.

"Let's drop him off in the middle of the Mediterranean Sea," Bahorel said. "With a raft," he added on a moment later.

"No, we need You-Know-Who," Musichetta said.

Combeferre frowned, "we're not letting Voldemort kill him either!"

"Not Voldemort, Cosette!" Éponine said. At the mention of his lover's name, Marius started screaming and banging on the door.

"That's the most human response we've got out of him," Jehan said.

"I still think he's possessed," Grantaire said.

"What do we do now?" Joly asked.

"It's just today, guys, we can do this," Enjolras said.

Early Sunday morning, Cosette stepped out of the airport. She smiled, but quickly frowned. She had thought her friends would be waiting for her. But apparently not. Cosette and her father went to their house and unpacked. Cosette checked her phone, but there were no messages.

"I'm going to head to the Musain café," Cosette said. Her father nodded as he unpacked two silver candlesticks.

Cosette was worried. The café was empty. Maybe they were playing a trick on her? But Enjolras and Combeferre would be here, working. Cosette sighed and walked out. She was walking down the street, when she saw them.

Marius was running on all fours, naked, insanely dirty, with a collar and leash. All of Les Amis was following him. Grantaire had a bottle brandished, and Bahorel was holding a club. They were shouting and calling after Marius, who had froze when he saw Cosette.

"Marius?" Cosette asked, tentatively. Marius whimpered and ran over to her. Cosette knelt down and hugged him. She turned to everyone else, who had caught up to them.

"What happened?!" she said. "I thought you guys would look after him!" They all exchanged looks. Cosette sighed and ruffled Marius's hair. "I don't think I want to know, actually."

Éponine grinned. "Never leave again, Cosette. Just don't. Madness will break lose."