How well do you know your child? Could you imagine your child as a murderer? What if the victim was another child? This shocking human drama, based on a popular comic series by Minoru Itoh, tells the story of two typical mothers whose lives are abruptly brought together through a tragic incident involving their sons.
Typical mother Satsuki Noguchi (Izumi Inamori) spent her days trying to balance her life as a wife to her hard-working husband Kazuhiko (Taro Yamamoto) and mother to their only son Tomoya (Issey Kakazu), a seemingly withdrawn fifth grader with whom Satsuki struggled to communicate.
Seiko (Yuka Itaya) and Hideaki Ozawa (Shiro Sano), living in the same neighborhood as the Noguchi family, were raising a rebellious junior high school daughter Mihoko (Umika Kawashima) and long-awaited first son Kiyotaka (Shion Sato) a second grader who was showered with much love and affection by his mother.
On that ill-fated day when Kiyotaka was reported missing and was later found dead, Tomoya was taken into custody by police as the prime murder suspect. What would possess a child to kill another child?  Tomoya slowly begins to open up about his innermost feelings as the hidden truth reveals the true motive behind his cruel act of violence.  Satsuki, as mother of the perpetrator, comes face-to-face with her son’s true self while Seiko, as mother of the victim, deals with her sorrow and anger. 
"AISHITERU (I Love You)" acknowledges the challenges of child-raising that parents face while providing a catalyst for parents to reflect on how well they truly understand their child and how best to raise their child in this complex, modern society.

故事主要围绕两个家庭。野口皋月（稻森泉饰）与丈夫和彦（山本太朗饰）及小学5年级的儿子智也（嘉数一星饰）一家三口过着平凡的生活。另一个平凡家庭，主妇小沢圣子（板谷由夏饰）和丈夫秀昭（佐野史郎饰）育有一女一子，中学生的女儿美帆子（川岛海荷饰）和人见人爱的小学2年级的儿子清贵（佐藤诗音饰）。
某天，清贵突然失踪，翌日他的遗体被发现……不久，智也被视为疑兇被警察局带走……
媒体大肆报导这宗小学生杀害小学生的事件，加害家庭一方因为受尽世人的指责和良心的责备而痛苦不堪。而受害家庭也因为儿子无故被杀而陷入痛苦的深渊。杀人动机随着智也的剖白而逐渐清晰，到底他的内心深处有着什么伤痛而导致他伤害素未谋面的清贵呢?
在现今越来越复杂的社会中，不管是为了养育下一代而抱有不安的父母，或是快成家立室的年轻人，都可能有着如何维系家庭和如何与子女相处，沟通的疑问。
本剧藉着儿童被杀事件，除了突显出「家庭爱」的主题之外，另一个重要的信息是副题的「包容」。本剧除了详细描写被害家庭如何由对加害家庭的痛恨到逐渐理解对方的心情外，也站在加害家庭的角度，描述疑兇的母亲如何自责和困惑于自己的儿子为何成为凶手的心情。