It started when Mira invited Wendy and Erza to have a girls' day and go shopping together. She hadn't expected for it to turn into a full out brawl between the guild.
Everything was going swimmingly at first. Wendy was trying on outfits she'd found in the store while Erza was still looking, and Mira was being Wendy's second opinion of sorts for the outfits she'd try on. Mira was an ex-model, after all. When Wendy was taking a longer time than usual changing, Mira walked over to where Erza was to strike up conversation to pass the time.
"Enjoying our girls' day?" Mira asked excitedly with a wide grin on her lips.
Erza looked away from the clothes rack she was glancing over and nodded with a smile of her own, "I always do. I'm kind of glad I postponed that mission I was supposed to go on with Gray today."
"I hope I wasn't interrupting anything… You didn't tell me you were going to spend the day with Gray." Mira said, a bit guilty.
"Nonsense." Erza said, waving her hand dismissively, "He said that he wanted to rest at the guild with Elfman, anyways. We're still on for tomorrow."
"'Cause you know I like to bring people together, not pull them apart." Mira giggled.
Erza narrowed her eyes and shot Mira a baleful glance, "Don't you have anything better to do than mess with people's love lives?"
"Oh, so you would say love is involved?" Mira teased, winking at Erza.
"How would you like it if I hassled you for details on your dating life?" Erza countered, crossing her arms.
Walking up to Erza's side and placing her interlocked hands on Erza's shoulder, Mira just formed a mischievous smile and quirked a teasing brow, "I think you already know.~"
A bead of sweat dripped down Erza's forehead as she muttered, "Now's hardly the time…"
"Hey, Mira-san! How's this-" Wendy stopped when she saw Erza and Mira standing together, "Erm- what are you two doing?"
"Being intrusive, apparently..." Erza groaned, giving Mira major side-eye, but stopped and whimpered because of the elbow Mira drove into her side.
"Wendy, that dress looks adorable on you! Some red jewelry and I bet it'd be complete!" Mira beamed, smiling widely.
"Right, got it!" Wendy replied with equal enthusiasm, running off and paying Erza and Mira's closeness no heed after that.
Erza grimaced and rubbed at her side once Wendy was gone, which only made Mira giggle, "I was just messing with you earlier, you know."
"The flirting, the elbow, or the love thing with Gray?"
"...Your pick!"
They left the mall a couple hours later, with Mira surprisingly teasing Erza only a few more times, rather than that being the only thing leaving her mouth. When they were walking back to the guild, the guild's doors were wide open, which wasn't too rare, but Mira could hardly see anyone inside. As soon as Erza set foot in the guild, something was dropped from the second level, right on top of her. She dropped to a knee under its weight, but it fell apart as soon as it hit her, and covered her completely in...strawberry cheesecake. Someone dropped an entire strawberry cheesecake on Erza's head. The guild members, who were hidden against the walls, let out a collective gasp, and the person on the second level dropped down, a worried look on her face.
"Oh, geez, Erza…" It was Gray who did that, "That was meant for Natsu, not you."
There was a flash of anger in Erza's eyes and she crouched down, ready to pounce, but Mira wrapped her arms around Erza's waist as soon as she jumped.
"Let's not kill anyone on our girls' day, okay, Erza?" Mira said, exhaling a nervous laugh. Gray was backing up with his hands raised in surrender, but Erza was actively trying to free herself from Mira's grasp.
"He ruined a perfectly good cheesecake!" She yelled, attempting to pry Mira's hands off her, but to no avail, "That's unforgivable!"
"Oh boy..." Mira said quietly to herself, moving to carry Erza into one of the back rooms, even with all her fighting. Once they were inside, Mira quickly let go of Erza and closed the door, standing with her back on the door so Erza won't rush through it. "Why don't we get you cleaned up first?" Mira said, forcing a smile on her face. Erza pursed her lips and glanced off to the side, scraping frosting off her cheek and eating it. "Without licking it off." Mira added, which only made Erza frown, muttering something about how earlier in the day, she probably would've joined.
"You have to help me get back at Gray." Erza said all of a sudden, about halfway through getting frosting and cake out of her hair.
"It was an accident, Erza. I'm sure he just wants to apologize." Mira replied, wiping off her arms since she got frosting on her when she grabbed Erza.
Erza walked up to Mira and placed her hands on the other girl's shoulders, a pleading look in her eyes, "It'll be the exact same mischief we'd use to get up to when we were younger, except not against each other this time."
Mira frowned, concerned, but eventually she gave in. "Alright...but nobody gets hurt, okay?"
"I promise. We can do something simple, like water balloons, or something."
"Alright…"
"Large water balloons."
"Erza…"
"Medium water balloons."
Once they were cleaned up and used the water nozzle to fill party balloons that the guild always had in storage, Erza gathered them all up and sent them to her weapons collection so she could requip them at will. They exited from the back room a few seconds later, with the guild falling silent as Erza made her way to a table and sat down, whereas Mira went back to her position behind the bar. Wendy ended up walking over to Mira, sitting on one of the barstools with Carla on the seat next to her.
"What happened in there, Mira-san?" Wendy asked curiously, tilting her head.
"I got myself roped into a revenge plot with Erza, eheh." Mirajane admitted with a nervous smile.
"I'm suddenly very afraid for Gray-san." Wendy rubbed her cheek, staring at Gray, who was talking to Elfman with his eyes on Erza.
"I am too, Wendy. I am too." Mira whispered back.
Erza walked up to the bar a few moments later, and Gray followed, standing beside her barstool and rubbing at the back of his neck.
"Look, Erza, I'm sorry about earlier. I can get you cheesecake to make up for it." He said, his gaze anywhere but on Erza at that point.
Erza almost seemed ready to accept his apology, but she eventually went back to wanting revenge. "That won't be necessary."
Gray frowned, taking the hint and walking back over to his seat. Right before he could sit down, though, Erza summoned the plethora of water balloons she had stored, sending most of them towards Gray but giving some to Mira so she could get her own shots in. Erza, however, put too much force in sending them over, causing them to explode all over Mira, just as they had Gray. Mira stood there, blinking, face void of emotion as water dripped off of her, as Erza and the rest of the guild as a whole gasped.
"Well, that backfired." Erza commented, holding her hands out to Mira, "Mira, I'm terribly sor-"
"Erza. I'll give you a headstart. Run." Mira said back, raising her eyebrows and tilting her head, just daring for Erza to resist her.
Erza gulped, taking a few steps back, but was shaken out of her thoughts by Gray shouting, "She ain't running nowhere!"
She turned just in time to see Gray tackling her, and after that, the entirety of the guild went up in arms, starting their own brawls. Mira vaulted over the bar and over to where Gray and Erza were wrestling, joining in herself.
"Hands off! She's mine!" Gray yelled, separating himself from Erza so he could push Mira out of the way.
"You deserved it!" Mira shouted back while grabbing Gray, that demonic voice underlying her words, "I didn't!"
"It was an accident!" Gray spat, trying to wrestle himself out of Mira's grasp.
Erza took the chance to sit up and put Gray in a chokehold, kicking Mira away, "It was a crime!"
As the fighting went on further, Wendy and Carla looked on from behind the bar, staring at the three-person fight between Gray, Mira, and Erza, and the occasional Elfman brawl with him yelling 'MAN!'
"I don't need clairvoyance to tell that the mission Gray and Erza plan to go on tomorrow is going to be tense." Carla said, obvious disapproval in her voice.
Wendy laughed nervously, a sweatdrop falling down her cheek, "Yeah, probably."