A/N: This is a one-shot requested by Dalma22. The idea was so perfect and Kendall and Katie have the best sibling relationship. Hope you enjoy!

Kendall Knight was walking through the lobby of the Palm Woods when he was stopped by his teacher, Ms. Collins.

"Kendall, do you have a moment?" she asked.

"Sure," he said, as he followed her to the classroom. He wondered why she wanted to talk to him. He was usually pretty good in school and it was only a couple of times that he asked Logan to do his homework for him. Ms. Collins sat down in her desk and Kendall sat on the top of the desk across from her.

"I wanted to talk to you about Katie," she said.

"Katie?" He asked, surprised. His little sister was a little devil but she was also very clever.

"Well with your mom away right now, you're the best option," she said.

"What's going on with Katie?" he asked, knowing that Katie could have pulled something big if Ms. Collins wished to speak to him about her.

"It's about her history grades," She said disappointedly, "They are much lower than her other grades and she told me that she can't seem to keep everything straight."

"Katie told us just last night that she was doing fine in school and needed no help," I said.

"Well, she lied," Ms. Collins said pulling out a folder that said 'Katie Knight' on it. She pulled out her latest history tests, which Kendall noticed were less than satisfactory. There was only one passed test out of the last four, and it was a 66%.

"This is just so unlike Katie to do so poorly," Kendall said.

"I was shocked too, but I thought that she told you," Ms. Collins confessed.

"Usually she does," Kendall said, feeling slightly disappointed in his sister's lie and schoolwork.

"Everything else is in the high 90's, it's just that history grade that is so low," she said.

"I'll talk to her about it," Kendall promised, "Is there anything else?"

"Yes, it's about her relationship with Heather Burns," she said slowly. Uh-oh, Kendall thought.

"They can't seem to get along. Apparently they have been in a fight for a couple of weeks now and sometimes it got physical. Katie spit her lip last week and Heather has a black eye currently."

"She told me she split her lip when she tripped and banged it against the table," Kendall said, growing frustrated with Katie's little lies.

"Again, she must have lied," Ms. Collins said, "It probably just means that she doesn't want help and want's to deal with it on her own."

"Katie will not stop until she wins," Kendall sighed, knowing that he was going to have to have a serious conversation with his little sister about lying.

"I hope you will be able to talk to her and get these two issues dealt with," Ms. Collins said.

"I will, I promise," Kendall said as he left the classroom.

Katie Knight was sitting on a bench in the Palm Woods Park, staring at her history book begging it to make sense to her. She had been struggling with history for a while but she didn't want to tell the guys. She didn't want them to know that she needed help with something, especially Kendall. She knew he loved her, but she didn't want him to know that she still needed some help. She prided herself on her independence, and needing help would ruin that. It also didn't help that Heather Burns kept getting better grades and flaunted it around when she knew Katie was struggling, but she didn't want to fight. When Heather attacked, she defended. She lied to the boys about the split lip because she didn't want them to know what was really happening. As usual, however, things didn't always go as planned when she saw an angry and disappointed Kendall walk into the park.

"Katie!" He called, not noticing her on the bench closest to him.

"What?" She demanded. He looked to his right as saw his sister with her history book in her lap.

"Do you have something you wish to tell me?" He asked, as she closed her book. She knew that he knew she was struggling in history when his eyes went right to her book and then back at her.

"Not really, no," she said.

"Well I think you do," He said glaring at her. Katie remained silent. Kendall poked her sides and the girl squealed.

"Do you want to talk about history? Or maybe Heather? Or the fact that you lied to me?" Kendall asked. Yup, Katie thought, Kendall was pissed.

"None of the above," Katie muttered, looking at the ground. Kendall sat down next to her.

"Katie, I want to help you but I can't do that if you won't tell me when you need help," Kendall said compassionately.

"But I don't understand why I don't get it. I study so hard for history but I can never keep the dates and people straight. I can't keep it in my head," Katie sighed.

"Katie, it's okay to ask for help. The guys and I all do, well, maybe not Logan," he said.

"But everything else makes sense to me. When doesn't history? Am I stupid or something?" She asked, looking up to Kendall.

"No, you're one of smartest people I know. Just because you don't understand one thing does not mean that you're stupid," Kendall said, looking down at her.

"But Heather keeps saying that I'm stupid and she does so well in history," Katie whined.

"Hey, Heather is Heather and you are Katie. You don't need to be anyone else but yourself. No one understands everything. But what is really important is that you lied to me," Kendall said seriously. Katie looked down.

"I didn't want to, but I would never hear the end of it if I told you guys. You would have found my weakness, and I don't like having a weakness," Katie said softly. That's not your only weakness, Kendall thought.

"Katie, everyone has a weakness."

"Even you?" Katie asked, raising an eyebrow, "And the guys?"

"James' weakness is his looks, but hair especially. Carlos' weakness is his big heart. Logan's weakness is pressure. My weakness is my loyalty to everyone I love. I would do anything to protect any one of you, even if I get in trouble," Kendall said in all honesty.

"So history is my weakness," Katie said with a small frown.

"Yes, it is. But you told two lies. The first being about your grades, the second being about your lip," Kendall said.

"Uh-oh," Katie sighed.

"Yeah, uh-oh. Ms. Collins said that you got the split lip in a fight with her, and you gave her a black eye. Is this true?" Kendall asked.

"Yeah," Katie said sheepishly, "But she got me so angry while she was attacking my grades and it's after every test that I lost it. We have honestly been non-stop fighting for a few weeks, but it only got physical twice!"

"Katie, you can't get into physical fights with people. It's not the guys you are fighting with but other people who are not used to the way we play."

"But I was just defending myself! She kept attacking me so I fought back the way I knew how," Katie said so earnestly that Kendall cracked a smile.

"Just don't get into any more fights with her, okay? If she keeps going after you and your grades tell Ms. Collins or me," Kendall said sternly.

"Yes, Kendall," Katie said.

"Good. Now let's look at that history book," Kendall said, taking the book off of Katie's lap, "It's not as bad as it seems. Flash cards help a lot, and I can also quiz you and help you study. When's your next test?"

"Tomorrow," Katie sighed.

"Then we have a lot of work to do right now," Kendall said. Katie smiled as Kendall opened up to chapter ten, otherwise known as The Civil War.

Katie and Kendall sat on that bench for the next several hours going over the facts and dates that Katie needed until she got them. Katie had flashcards in her backpack and was surprised by how much making them helped her understand. Katie didn't even notice how late it was getting until Kendall put her book down.

"We should go home soon. The guys will be back with dinner soon," he said.

"This is much easier when someone is helping me," Katie said as she started to fill her backpack with her books.

"Yes, it is, but you know you are going to be punished for lying to me, right?" Kendall said, thinking about using Katie's other weakness.

"Do I have to? I just spent hours studying. Isn't that punishment enough?" Katie said, using her eyes to try and get him to agree.

"Nope," Kendall said, popping the "p." Kendall poked her side and Katie knew exactly how he planned to punish her.

"No, please Kendall just ground me or something," Katie begged.

"Sorry, baby sister," Kendall grinned. Katie stated to run away, but Kendall was much faster and easily caught and started attacking her sides mercilessly. Katie squealed and fought to get Kendall off of her, but he wouldn't let her be.

"I…can't…breathe," Katie gasped ten minutes later, and Kendall finally let up.

"If you lie again, the punishment will be the same," Kendall promised.

"Okay, okay, okay," Katie said, her eyes growing wide at his threat, "I won't lie. I promise."

"Good," Kendall said, extending a hand to help her up. The two siblings headed back to the apartment and found dinner waiting for them.

"Hey, where were you?" Logan asked from the kitchen.

"I was in the park, helping Katie study and punishing her for lying," Kendall said.

"What did she lie about?" Logan asked at the same time James asked, "How did you punish her?"

"She lied about her history grades and about how she got the split lip last week," Kendall said, "And I used her weakness."

"Which would be?" James questioned. Katie looked at Kendall with pleading eyes. He ignored them.

"She is very ticklish," He smirked.

"Kendall!" Katie yelled.

"Wait, what? Why didn't we know this?" Carlos asked.

"We did," Logan said, "Katie just never got in trouble."

"I think she still needs some more punishing," James said.

"No, Kendall did enough," Katie said quickly.

"Yeah, but you also lied to them, so I guess they get to punish you too," Kendall grinned as he grabbed a water from the fridge.

"I HATE YOU, KENDALL KNIGHT!" Katie screamed as her sides were once again attacked. Once they were all done punishing Katie, they sat down to dinner. After dinner, Kendall and Katie studied some more so that she was all ready for tomorrow's test.

Kendall paced around the apartment the next afternoon nervously. Katie wasn't home yet and he was nervous about her test. He wanted her to do well on it and he really hoped she did. When the door opened to the apartment, he immediately looked towards it. Katie walked in with her head down. Kendall felt a pang for his sister, thinking that she did not do well on the test.

"How was the test, Katie?" He asked, and his heart sank when she didn't look up. Slowly she raised her head and he saw a huge smile on her face.

"I got a 97! I only missed one question!" She said enthusiastically.

"That's great, Katie!" Kendall said, giving her a hug, "You had me scared when you walked in."

"That was the plan," She laughed.

"I'm proud of you, baby sister."

"You didn't hear the best part. Heather only got a 94!" Katie smiled.

"Did you gloat?" Kendall asked.

"No, because I didn't like it when she did that to me so I didn't do it to her," Katie said.

"Good," Kendall smiled, "And what will you never do again?"

"I will never lie again to my big brother or mom or the guys," Katie said.

"Right, and what happens if you do?" Kendall asked, a smirk playing on his face.

"I will get attacked with tickles," Katie said, scrunching her face in disgust.

"Correct," Kendall smiled. Katie started to make her way to her room, but turned back and gave Kendall a hug.

"Thanks for helping me, big brother," She said.

"Anytime, baby sister, anytime," Kendall said.