Disclaimer: I do not own the Marvel Cinematic Universe, nor do I ever remember pulling an April Fools' Day prank (but if I have, it was most likely seriously lame).

At 2:59 on the morning of April first, every resident of Avengers Tower received an email.

"AVENGERS TOWER IS A PRANK-FREE ZONE FOR THE NEXT TWENTY ONE HOURS. TONY AND STEVE INCLUDED. ANYONE WHO DOES NOT TAKE THIS SERIOUSLY WILL FACE MY WRATH."

Underneath these words was a picture of Pepper Potts, a disappointed frown on her face.

Darcy sighed when she saw it. So much for that pop rocks and coffee experiment she'd wanted to try with Bruce.

She mixed up some blueberry muffins and took them out to bake in the common kitchen, which she hoped would draw several Avengers out of hiding places. The first one to appear came from a nearby vent.

He was pouting. "Are there any April Fools in these brownies?" he asked.

"They're muffins," she corrected, "So, if you think they're brownies, then you're only fooling yourself. Also, no. Are you kidding me? I don't want an angry/sad Pepper face."

"How come she singled out Tony and Steve? I bet I'm better than both of them."

"At pranking?" Darcy asked, tapping the tin and watching as muffins bounced across the counter. "You won't get to find out today."

He peeled the paper off a muffin and stuck the blueberry goodness in his mouth. "Someday," he threatened.

Darcy took the remaining muffins to the lab with her.

"Were you planning anything for today?" Jane asked Bruce when he came over to take one.

He shrugged. "I'm not usually interested in that kind of thing, but I'm pretty relieved I don't have to worry about Tony zapping me with a cattle prod or anything."

"Yeah, he's got the most to lose if he has to face that frown," Darcy considered.

Natasha and Thor were sparring when she walked past the gym.

"Hey did you guys see that email?" she asked when they took a break from hitting each other.

"Yeah, April Fools' Day is canceled? I don't really mind. It just means I don't have to get back at Barton for whatever ill-conceived thing he tries to pull this year."

"I was looking forward to celebrating this Midgardian holiday by pouring a drink for Tony. I read about a very amusing trick with salt instead of ice."

Nat made a face. "And whiskey?" She consulted Darcy. "Is it possible to kill a Norse god?"

Darcy shrugged. "You can definitely tase one," she told her, with a grin at the god in question.

Later, she was pulling salad dressing out of the refrigerator and setting it on the table for the group dinner. Steve was making salad.

"Did you do a lot of pranks in the army?" Darcy asked.

Steve nodded. "I had more played on me before I was…" he gestured at himself with the spoon in his hand. "So I'm pretty familiar with them."

"Is that why you got named specifically, you think?"

He shrugged. "Maybe. I did threaten Tony about starting a prank war once in front of Pepper, so maybe that's why."

"What's the best one you've ever pulled?"

"Mmmn..." Steve thought about it. "There were a few times I messed with one of the Commandos, or Bucky, just because I could. I think it's really funny when someone underestimates me. Like once when we were in northern France, there was this girl that—" Steve turned to bring the salad to the table, and noticed that his audience no longer consisted of only Darcy. Tony, Clint, and Natasha were all there, listening intently.

"A girl that what?" Natasha prompted.

He cleared his throat and blushed. "It's probably not a very appropriate story for dinner conversation."

"So Barton," Tony said as soon as Thor had brought Bruce and Jane from the lab and he'd eaten what he considered a sufficient amount of Darcy's lasagna (three helpings and whatever he could get away with stealing from Bruce's plate). "What crazy crap did you try to pull on Romanov today?"

"Uh, nothing?" the slightly annoyed archer replied. "Because Pepper would get all wrathful. I prefer her pleasant and non-wrathful."

"What? Seriously?" Tony gaped.

"Thor didn't season your drink, either," Natasha informed him.

Tony eyed the empty glass of scotch in front of him. "Wait, none of you got up to anything today because of that email?" He looked around at all of them, and they shook their heads, shrugged, and generally replied in the affirmative.

"Pepper's word is law around here," Jane said.

"Wow, that's…" Tony dug into his pocket for his phone, and dialed Pepper up. "Hey honey," he said after they heard her indistinct greeting. "Um, know how when I texted you earlier and said nobody had pulled any pranks on me today?"

He paused for her response, then continued. "Well, I guess it's because I hacked your email this morning and they all got the idea that you'd be mad if they did. Oh, and I also emailed a bunch of poop emojis to that Senator's aide who won't stop flirting when he asks you for campaign contributions. Love you!"

He hung up the phone and dug into his salad, then looked up, unashamed, at all the glares he was getting from the rest of the people at the table. "What? Like Pepper would send you a picture of herself, much less that one."

"Why did we not see through that?" Bruce asked, as Tony's phone began to ring. Angrily.

"It is because we hold Miss Potts' word as sacred," Thor pointed out, reaching for the last of Darcy's blueberry muffins after Steve took the second-to-last. "We know she would not lie to us."

Darcy watched Thor put the entire muffin in his mouth and Steve carefully remove the paper before taking a huge bite.

"Okay, full disclosure?" she said, ignoring the muffled shouting coming from Tony's phone. "I used frozen blueberries in those muffins instead of fresh."

The mostly intact baked goods fell from Steve's mouth and bounced onto his plate. Thor continued munching, unperturbed. Steve, however, looked from the muffin to Darcy, horrified.

"I trusted you!" he confessed, looking honestly hurt.

Darcy smiled apologetically. "April Fool?"

Tony abandoned his dinner and walked away, trying to interrupt the irate Pepper with an occasional murmured apology.

"So we've still got four hours and change left," Clint pointed out.

"If you even think about it, I will tell everyone what you did on that stakeout in the Netherlands in 2006," Natasha stated blandly.

"Skipping one year of pranks won't hurt me," Clint decided immediately.

"Actually, I think I want to hear this story," Bruce said.

"You don't," Clint warned him.

Natasha grinned.

"He really doesn't."

"Would you rather not have any muffins at all?" Jane asked Steve.

"Yes," he replied, crossing his arms and looking as though he was trying not to pout.

"If you buy me blueberries, I'll make a whole batch just for you," Darcy told him.

He didn't hate the sound of that. "Really?"

She nodded.

"She will also make cherry cobbler if you bring her cherries in a metal can," Thor said.

Darcy knew she was forgiven when Steve picked up the uneaten muffin and stuffed it back in his mouth.

"What we really need to do now…" Bruce began, looking over his shoulder in the direction Tony had wandered, "Is plot our revenge."

"We should spray paint the suit purple," Jane suggested. Thor laughed.

"Itching powder?" Steve added.

"Swap out his tunes," Clint volunteered.

"Or his alcohol!"

Natasha grinned and rubbed her hands together. "This is a brainstorming session I can get behind!"

Darcy smiled. Nothing united the Avengers like a common adversary.

"You guys get started; I'll text Pepper."

Author's Note (Friday, April 1st 2016):I love Avengers Domestic Fluff, and I hope you do too! Find me on ao3 & tumblr under the same handle, on twitter with Stella AT CoAwesomeness, or on my blog, iwillwriteyourfic DOT blogspot DOT com.