Exactly three hours after the last person (Tony) had gone to bed, Natasha knocked on Peter's door.  He groaned as the door opened and Natasha walked in.  She had FRIDAY turn on the lights, but keep them dim, and went to wake up Peter.  When he realised it was Natasha, he forced himself awake.  He sat up and crawled under his bed to grab the backpack.  He pulled out the megaphone and handed it to Natasha.  She grinned.  He grabbed the siren light and the air horn, careful not to press the air horn on. 

He quietly followed Natasha out of his room and down to guest floor where all the Avengers were staying.  They woke up Wanda who was with Vision.  Vision gave them strange looks but it didn't take Wanda long to convince him not to do anything.  She warned him they were going to make a panic, but he should just stay in her room and she would tell him telepathically when to come out.  He nodded and wished them luck.  They walked to the end of the hall right by Steve and Clint's room.  Wanda grabbed the air horn and raised it above her hand.  She waited for Natasha's signal then pressed down on it.  Peter flicked on his siren light and held it above his head.  Natasha started yelling into the microphone and banging on doors as they ran down the halls.

"It's an emergency!  Get up!  Hurry!"  she screamed into the megaphone.  They raced down the hall then turned around to see everyone shoving each other down the hall in a hurry to escape.  Natasha had told Bruce ahead of time that he should stay on a different floor and then explained why.  The last thing they needed was the Hulk. 

"Where's the emergency?"  Steve yelled, stumbling down the hall shirtless and in flannel pants.  His hair was a mess and he looked truly terrified.  Sam was only in his boxers and looked like he was about to wet himself in fear.  Clint was looking very disheveled with his hair pointing every which way and his Brave Merida sweatpants and pink t-shirt.  Bucky just wandered out of his room sleepily, rubbing his eyes then glaring at the three in the living room.  When the others all saw Natasha, Wanda, and Peter laughing in the living room, they calmed down and glared at them.

"You should have seen your faces,"  Natasha managed to say between laughs.

"That was hilarious,"  Peter gasped, clutching his stomach.  Wanda was laughing too hard to say anything.

"Haha, that was great,"  Sam said dryly.  He had evidently not recovered from his undignified panic.  "Can we go back to sleep now?"

"FRIDAY, you got that on video, right?"  Peter asked, looking up at the ceiling as he slowly calmed down.

"Of course,"  FRIDAY replied.  Clint and Sam groaned, turning around and walking back to their rooms.  Steve just smiled and shook his head.

"No more,"  he said, pointing at the three before leaving.   They nodded, tears in their eyes from laughing too much.

"We couldn't do more anyway,"  Natasha told him.   "You'd be expecting it."  Steve just waved goodnight over his shoulder then shut the door to his room.  Bucky followed close behind after muttering something in Russian to Natasha.  Wanda collected the supplies back up then returned to her room as well.  Natasha took Peter back upstairs to his room and as they were walking past Tony's room, they both stopped.  They looked at each other then grinned.  Peter set the siren light at the bottom of the door and picked up the air horn.  Natasha gave the signal and he blasted it while she yelled.  Tony came bursting out of his room and tripped over the siren light.  Natasha couldn't continue yelling, dissolving into more laughter.  Peter let go of the air horn and laughed with her as Tony groaned and rolled onto his back.

"You're both from the devil,"  he mumbled, dragging a hand down his face.  Peter just laughed and asked FRIDAY if she had gotten that on video too.  Of course she had.  "I swear, you and your pranks will be the death of me.  Wait, where's Wanda?"  Tony asked, standing back up and looking around for the third companion.

"She's downstairs,"  Peter said.  He explained what they had done on guest floor and that doing it to Tony had been a split second decision.  Tony's eyes widened when they said guest hall, remembering Bruce was down there.  "Don't worry, Uncle Bruce is on a whole different floor.  We warned him ahead of time."

"You didn't tell me you were doing it up here, too,"  Bruce said, rubbing his eyes as he walked down the hall.  Thankfully he had been on the other end of the house and been sleeping with ear plugs in anyway.

"Sorry, Uncle Bruce,"  Peter said, turning off the siren light.  "It was a last minute idea."

"Well I hope you got both on video,"  Bruce said.  Peter nodded happily.  "Good.  I want to sleep."  He turned around and returned to his room.  Tony sent Peter off to bed so he gathered up their supplies, accidentally set off the air horn, then returned to his room.  Natasha went back downstairs to her room and found Steve, Sam, and Clint were still awake.  Apparently they weren't tired enough to go to sleep so they were going to go down to the training room for a while.  Natasha didn't see Wanda or Bucky among them and peered into Wanda's room first.  She was fast asleep with Vision beside her.  Natasha smiled and shut the door, going down the hall to look for Bucky.  He was fast asleep as well.  She shut his door and walked into her own room, laying down to try and sleep.  However, she couldn't and decided to join the boys downstairs in the training room.  When she saw them all running laps at full speed, she turned back around and went up to her room.  She wasn't that desperate to fall asleep.