Hitachiin Triplets: Long Lost Sister

Kameko turned around and yelled "Mother!". With tears of joy while running towards her mother, Kaoru stayed near the window standing with his jaw open. "Kameko-chan! I thought the Hitachiin family lost you forever, but you've come back from France.", Mrs.Hitachiin said with tears. "I did come back Maman, I even graduated and became a fashion designer!", Kameko said in a cute & french accented voice. Hikaru opened the bathroom door a bit and took a peek, after he saw his mother hugging the "hyper bunny" he fainted in disbelief. "Oh Kameko, you seem just like me when I was young... you're even like me now: sweet and creative in the fashion industry.", Mrs.Hitachiin said as they continued their embrace. Kaoru twitched at what his mother said. She's not "sweet", she's a wild animal, baka mom, he thought as he watched them talk. Then Kaoru decided to just interrupt, "Pardon me Mother, but who the hell is this girl?"

Mrs.Hitachiin glared at him, "Kaoru, this is you and- Hikaru's younger sister. You and Hikaru were actually born as triplets with Kameko-chan... you just never knew because she was kidnapped from the hospital and we've never seen her since." Kaoru kept looking at Kameko as his mother said this, and underneath that innocent look on Kameko's face there was a devious glare that shot into his eyes. Then he began to glare at her, their mother looked at Kaoru and said, "Kaoru, why are you glaring at sweet Kameko?".
"Oh no reason, mom. Just studying her.", he said casually.
"Hmm, alrighty then, I guess I'll leave you two alone now... and where's Hikaru?", Mrs.Hitachiin asked as she was closing the door.
"In the bathroom... I'll go get him."
Then the "triplets" mom closed the door and left.

After she left, Kameko began to speak up. "Kaoru-oniisan, you do know it's not good to glare at me...", she tapped her foot harshly on a nice carpet. She began to make the evil glaring face again. Kaoru twitched and ran into the bathroom. He opened the door and accidently hit a dead-looking Hikaru. "Ehhh!? Hikaru! Get up!", Kaoru yelled as he shook Hikaru by his shirt, just as before, he was freaked out because of Kameko and now the twins were going to be in a state of panic again. Hikaru woke up and asked what just happend. Kaoru explained to him about the strange truth of Kameko and them born as triplets. "NANI!!?", Hikaru shouted in shock. "Yeah, I said that too, and now I'm wondering if it's true or mother's just pulling a stupid trick on us.", Kaoru replied. "Maybe it's her vengeful way of getting back at us for all the pranks we pulled in our childhood...", Hikaru shivered fearly.
"Probably is, but how can she be our triplet? She's a bit shorter than us..."

"Hmm, yeah yeah.", Hikaru nodded.
"... but then again, we maybe fraternal triplets. Another thing is that I've seen this fiery look in her eyes, like underneath that 'sweet and creative' exterior she has when mom's around is just a ridiculously believable disguise!", Kaoru exclaimed.

Hikaru just nods at this and they take a peek out the door. Then they saw Kameko's evil face there, "AH!", the brothers shouted and slammed the door. "Neh, neh, Kaoru, I thought we were pranksters, shouldn't we do something mischievious to her so we can get rid of her?", Hikaru suggested as he breathed nervously.
"Sure, I guess, what are we gonna do?"
Hikaru grinned evilly, "How 'bout shove her head down the toilet when she runs in here, kukuku." clasping his hands.
Kaoru made a frown at him like as if it was too irrational. "Please Hikaru, that is so kindergarten, can't you think of anything better than that?"

Hikaru lost his evil grin and just started to think.
"I KNOW!", he said after a few minutes of thinking. "What? What are we gonna do!?", Kaoru asked with a big smile. Hikaru told him the plan in his ear. As the mischievious Kaoru and Hikaru talked, Kameko was standing in front of a locked bathroom door, bored and she felt like breaking the door down, but no she waited...