I do not own H2O: Just Add Water. A bit of an Alternate Ending that I added in as well.
This is also my first time writing in this fandom so I hope you enjoy!

This is taken from the episode Sea Change

Ever since the announcement that her sister was missing, Kim Sertori fell in to an unusual silence. As she listened to details about what happened to her sister, the young girl felt something that made her feel weird inside. She didn't let on about it, didn't show anyone what she was feeling, but Kim was scared for her sister and maybe even guilty. She wondered if it was her own fault that her big sister took off. What had driven her to run out of the house? Was it simply because of how Kim acted towards her? She knew that she was a brat and frankly, she was most proud of it. But was that why Cleo had run away? It seemed pretty harsh now to call her sister a loser the moment she ran out the door.

"If Cleo's still missing when the twenty-four hours are past, the police will need photos," Emma spoke up, bringing Kim out of her daze. She sounded so grim, something that wasn't usual for the blonde.

Kim watched as her dad walked over to mantle where a picture frame of Cleo sat. He picked it up, looked it over and brought it over to Kim to ask what she thought. Seeing the picture of her sister, Kim could feel tears threaten to rise; emotions bubbling under the surface. The picture of her sister was with Kim, back when their mother was still living at home. The two of them looked so happy and Kim felt ready to burst.

"She's looks really pretty in this one," Kim spoke, agreeing with her father on his choice of picture.

Another pang of guilt. Kim wasn't sure how long she could let this feeling last for. Of all the times she had been bratty to Cleo, this was one of the times where Kim wished that she never was the way she was. Suddenly, everyone heard the door open and they turned to look. In walked Cleo and Kim felt relief flood her heart.

"Hi everyone," Cleo greeted, walking in the door all embarrassed.

"Cleo," Don called. He got off the sofa that he was on and rushed to his daughter.

"I'm sorry I let you worry, dad," she apologized.

"Are you safe?" He asked, more worried about that than anything else.

"I'm fine." Sighing, Don took his eldest daughter into his arms. "You can thank Lewis for that," Cleo finished.

Kim looked over at the exchange that then took place between her sister and her friends, all saying that they were glad she was safe, and that they should have been there for her. Hearing this, Kim felt relief flood her as well, knowing that her sister had come home safely. She listened to the conversation as her father wrapped an arm around her shoulder and held her close. Everything was going to be alright.

After everyone had left and the house was back to it's usual quiet ways, Kim left her room and walked down the hall to her sisters, where she knocked on the door.

"Who is it?" Cleo called from the opposite side of the door.

"It's me..." Kim replied.

"Go away Kim, I'm not in the mood for your attitude," Cleo said, the tone in her voice sounding weary.

Guilt...that's all she felt when Cleo called her out on it. Kim leaned against the door, her hand ready on the handle to open.

"Cleo, please...let me in. I just want to talk to you," Kim explained.

Hearing a sigh and a ruffling of sheets, Kim leaned away from the door as it opened to reveal her sister clad in pajamas. Her make-up was wiped off and the young sister could see how worn out Cleo was.

"What is it Kim? Can't it wait till morning? I'm tired," Cleo whined.

"No, not really. Can I come in?" Kim asked.

Nodding, Cleo moved out of the way for her sister to come in and the two sat on the bed. Kim looked at her sister and then averted her gaze, feeling shame and that nagging feeling of guilt still.

"Cleo, I'm really sorry for how I acted earlier today. I should have just done what you asked. Maybe then, you wouldn't have run away," Kim apologized.

Hearing the words come out of her little sisters mouth, Cleo was surprised. Since when did Kim ever apologize for her actions and sound so sincere about it? Then remembering all that happened today, the older sister decided to hear the child out. She didn't say anything, just gave Kim an encouraging nod.

"Ever since you went missing, I was worried just as much as anyone else. I was scared about what could have happened to you," Kim started to explain.

"Kim, that's so sweet of you..."Cleo started to say.

"I'm not finished. Cleo, I'm...I'm so...sorry for how I act. Ever since mom left...I haven't been the same. And when you went missing..." Kim broke down in tears, unable to finish her sentence.

At first a bit surprised and shocked by her sisters breakdown, Cleo realized that her little sister was fragile in that moment and for once, she didn't rub it in her face. She didn't have any catty thoughts run in her head for her baby sister. Instead, Cleo felt her natural compassion push through and she pulled Kim in to a hug. She rubbed her sisters back as Kim sobbed in to her shoulder. Cleo pulled her closer and in that moment, the bond between the Sertori sisters grew a bit stronger; the fragile relationship slowly mending together.

Maybe this wasn't so bad after all. Cleo didn't mind this moment and she soaked it all in, not wanting it to end. Despite how fragile Kim was now, there was no doubt that she would forget all about tomorrow and go back to her bratty ways. For now, Cleo did something that she never got to do for Kim and that was to take care of her.

Despite what Kim would think later on, she really did care about her sister.

Hope you enjoyed that. If you did, leave a review and let me know what you think!