A.N. Hi! This is my first time writing in either of these fandoms so, please bear with me and give any suggestions along the way. This is only the prologue, though I have four chapters already written and will try to write more in the coming days. I probably should be updating my other stories, but this wouldn't leave my head after I read "Big Time Siblings" by Nichole Monroe. So, here it goes. Hope you enjoy.

Disclaimer: I own neither Criminal Minds or Big Time Rush. I wish I did.

Prologue

"Never forget who was with you from the start." -Unknown

She smiled down at her sleeping baby sister as she hung one of her butterflies above Katie's crib. It was her present to her little sister as she got ready to head off to college.

Jennifer Jareau, or JJ as her friends call her, walked out of her half-sister's nursery, grabbed her final bag, and headed out to her old subaru, putting the bag in the passenger seat. She turned around and looked up at her families two story house. It reminded her of her old home in Pennsylvania. She didn't like thinking of that house and the bathroom where she had found her sister, Rosaline. That was eight years ago. Her family had stayed together for about a year, but then her parents split because they couldn't stand the weight of Rosaline's actions any longer. Her mom and her had moved out here to Minnesota a few months after the divorce. A year after the move they had meet Kyle Knight, and her mother had fallen in love. Kyle was pretty cool, nice, and handsome, so JJ did object. A year later they got married. A year after that and JJ had her first step-sibling, Kendall. Two and a half years later and Katie Rosaline Knight was born, and here they all were six months later with her mother having two new kids and her going off to college.

She snaps out of her stupor and walks back into the house to say goodbye to everyone else. As she opened the front door she was greeted by a gasp coming from the living room and a somewhat clumsy four year old boy with dirty blonde hair falling into his eyes running out of said room with his father following behind him. JJ bent down and picked up the toddler who clung to her shirt.

Kyle, at her confused look, said, "He thought that you left without saying goodbye and wouldn't listen to us say that you'd be right back."

She nodded and pulled the boy off of her shirt and held him so they were face to face and said, "I would, I will, never leave without saying goodbye to you. I will be here for you whenever you need me." Little did she know that she would break that particular promise.

She set the little boy, who was now crying even harder, down. JJ approached her step-father and gave him a humongous hug. She then turned to her mother, Jennifer Knight, who was standing by the couch with tears running down her cheeks and gave her a huge hug.

"I love you so much," her mom said into her hair and JJ nodded silently, knowing that if she opened her mouth she would start crying. She waved to her parents and brother as she walked back out to her car and drove off towards the next part of her life.

Thirteen years later Jennifer Jareau-LaMontagne woke up from the dream, memory, in the bed she shared with her husband Will. She stared at the ceiling as she thought of her family. How long had it been since she had seen any of them? Oh ya, four years ago when she had Henry and her mother came up too help with them. The last time she saw her siblings was six years ago after Kyle died in a car accident. The last she heard from them was almost three years ago. Last she knew Katie was an energetic and smart ten year old that was blazing her way through middle school, and Kendall was the captain of his hockey team which he played on with his three best friends Logan Mitchell, Carlos Garcia, and James Diamond. Had it really been three years? It must have.

JJ decided that she would call her mom to catch up after work which, after a quick check of her clock, she was due to in three hours. She snuggled up to Will and went back to sleep for the last two hours of peace she would get in a while.

A.N. I hope you liked it. Read, Review and Enjoy!